• Korean Journal of Construction Engineering and Management
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• v.17 no.2
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• pp.31-38
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• 2016

In a construction project, the portion for maintenance costs for a building is considerable compared to the initial construction cost. As such, Life Cycle Cost (LCC) analysis is being increasingly utilized to assess the design value of engineering work in Korea. Additionally, the Public Procurement Service in Korea announced that it will be mandatory for all domestic construction projects to adopt BIM. Furthermore, the paradigm for architectural design has shifted from 2D to 3D, and to BIM, which includes a data management system. Within this background, however, there is currently no adequate BIM-based LCC analysis software and the requirements of cost estimation for repair and replacement cost for a building is not completely adequate in BIM tools such as Revit and Archicad. Therefore, this study suggests a process of cost estimation for repair and replacement (R&R) cost based on IFC data. First, we analyzed existing R&R criteria and defined BIM-based requirements when calculating R&R costs. These requirements were extracted from relevant IFC data. Subsequently, this was saved to a database and a BIM-based database was built for R&R cost estimation. Finally, this database was connected with external databases such as R&R Criteria DB and Cost Information DB to calculate R&R costs. This process is expected to improve upon the traditional process of cost estimation of R&R cost by applying a BIM model. The proposed process can contribute to a further standardizing of BIM-based LCC analysis thru application to initial construction costs, energy costs, and other maintenance costs.

• Korean Journal of Agricultural and Forest Meteorology
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• v.17 no.4
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• pp.358-383
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• 2015

The concept of 'carbon footprint' has been developed as a means of quantifying the specific emissions of the greenhouse gases (GHGs) that cause global warming. Although there are still neither clear definitions of the term nor rules for units or the scope of its estimation, it is broadly accepted that the carbon footprint is the total amount of GHGs, expressed as $CO_2$ equivalents, emitted into the atmosphere directly or indirectly at all processes of the production by an individual or organization. According to the ISO/TS 14067, the carbon footprint of a product is calculated by multiplying the units of activity of processes that emit GHGs by emission factor of the processes, and by summing them up. Based on this, 'carbon labelling' system has been implemented in various ways over the world to provide consumers the opportunities of comparison and choice, and to encourage voluntary activities of producers to reduce GHG emissions. In the agricultural sector, as a judgment basis to help purchaser with ethical consumption, 'low-carbon agricultural and livestock products certification' system is expected to have more utilization value. In this process, the 'cradle to gate' approach (which excludes stages for usage and disposal) is mainly used to set the boundaries of the life cycle assessment for agricultural products. The estimation of carbon footprint for the entire agricultural and forestry sector should take both removals and emissions into account in the "National Greenhouse Gas Inventory Report". The carbon accumulation in the biomass of perennial trees in cropland should be considered also to reduce the total GHG emissions. In order to accomplish this, tower-based flux measurements can be used, which provide a direct quantification of $CO_2$ exchange during the entire life cycle. Carbon footprint information can be combined with other indicators to develop more holistic assessment indicators for sustainable agricultural and forestry ecosystems.

• Journal of Korea Society of Industrial Information Systems
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• v.4 no.3
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• pp.1-7
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• 1999

An important task for any software project manager is to be able to predict and control project size. Unfortunately, there is comparatively little work that deals with the problem of building prediction methods for software size in fourth-generation languages and database projects. In this paper, we propose a new estimation method for estimating for software size based on minimum relative error(MRE) criterion. The characteristic of the proposed method is insensitive to the extreme values of the observed measures which can be obtained early in the development life cycle. In order to verify the performance of the proposed estimation method for software size in terms of both quality of fit and predictive quality, the experiments has been conducted for the dataset Ⅰ and Ⅱ, respectively. For the data set Ⅰ and Ⅱ, our proposed prediction method was shown to be superior to the traditional method LS and RLS in terms of both the quality of fit and predictive quality when applied to data obtained from actual software development projects.

• The KIPS Transactions:PartD
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• v.9D no.5
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• pp.865-876
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• 2002

Successful project planning relies on a good estimation of the effort required to complete a project, together with the schedule options that may be available. Existing software effort estimation models are present only the total effort and instantaneous effort function for the software life-cycle. Also, Putnam presents constant effort rate in each phase. However, the size of total effort varies according to the software projects under the influence of its size, complexity and operational environment. As a result, the allocated effort in each phase also differs from one project to another. This paper suggests models for effort allocation in planning, specifying, building, testing and implementing phases followed by the project size and development types. These models are derived from 155 different projects. Therefore, these models can be considered as a practical guideline in management of project schedule and effort allocation.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.7 s.124
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• pp.572-578
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• 2007

Two stroke low speed diesel engines are widely used for marine propulsion or as power plant prime mover. These engines have many merits which includes higher thermal efficiency, mobility and durability. Yet various annoying vibrations occur sometimes in ships or at the plant itself. Of these vibrations, torsional vibration is very important and dictates a careful investigation during the engme's initial design stage for safe operation. With the rule and limit on torsional vibration in place, shaft strength fatigue due to torsional vibration however demands further analysis which possibly can be incorporated in the classification societies' rule and limit. In addition, the shaft's torsional vibration stresses can be calculated equivalently from accumulated fatigue cycles number due to transient torsional vibration in time domain. In this paper, authors suggest a new estimation method combined with Palmgren-Miner equation. A 6S70MC-C ($25,320ps{\times}91rpm$) engine for ship propulsion was selected as a case study. Angular velocity was measured, instead of shaft's strain, for simplified measurement and it was converted to torsional vibration stress for accumulated fatigue cycle numbers in shafting life time. Likewise, the accumulated fatigue calculation was compared with shaft fatigue strength limit. This new method can be further realized and confirmed in ship with two stroke low speed diesel engine.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.2
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• pp.107-112
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• 2015

Carbon emissions in construction stage is very high because lots of construction machines and materials are required to be used at a road construction stage. Many researcher carried out application of carbon emissions estimation methodology during the life cycle of road infrastructure in order to reduce greenhouse gas emissions in the road sector. But the calculation of carbon emissions is difficult because data collection is difficult and calculation procedure is complex. In this study, a basic unit of carbon emissions in construction stage of the road infrastructure was developed in order to get the quantitative determination of carbon that occurs. Carbon emissions of the expressway and common state road was calculated by using the basic unit of carbon emissions and application plan of basic unit of carbon emissions are presented.

• KIEAE Journal
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• v.10 no.4
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• pp.101-109
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• 2010

As global warming progresses, nations around the world are trying to reduce emission of $CO_2$ that accounts for the greatest portion of greenhouse gases. To reduce $CO_2$ emission, it is first necessary to estimate $CO_2$ emission of each industry. Government authorities estimate basic unit of $CO_2$ emission from re-bar that is one of the key materials of construction industry with LCA technique (Life Cycle Assessment). However, basic unit of $CO_2$ emission varies from organization to organization. The Ministry of Land, Transport and Maritime Affairs (2004) publishes it 3.48($TCO_2/ton$) and 0.30($TCO_2/ton$) with input-output analysis while the Korea Environmental Industry & Technology Institute (2008) defines it as 0.34($TCO_2/ton$) with process analysis, which indicates ambiguity in application of basic unit of $CO_2$emission. Based on the analysis of conventional methods used for estimating the $CO_2$ emission, therefore, this research suggests existing problems on the methods and focuses on proposing an strategy to effectively estimate the basic unit of $CO_2$ emission according to the energy consumption limited to the re-bar production in steel mill in order to overcome the problems. The result of this research is expected to be helpful in calculating and reducing $CO_2$ emission.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.156-162
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• 2004

In this paper, a technique that estimate the optimal capacity of the solar-wind hybrid power system for minimizing the total monthly electric power expenses is presented. The hybrid power system is assumed to be operated in connection with the utility power system and electric bill be paid for the power not covered by the hybrid system generation. Monthly generation cost is estimated based on total life-cycle cost analysis. The monthly utility power bill is assumed to be increased quadratically in proportion with the net utility power consumption which is the difference between the total monthly load minus the hybrid system generations. Test results demonstrate applications potential of the proposed technique.

• Korean Journal of Construction Engineering and Management
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• v.19 no.4
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• pp.82-92
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• 2018

Considering that earlier stage of construction project has a great influence on the possibility of lowering of environmental load, it is important to build and utilize system that can support effective decision making at the initial stage of the project. In this study, we constructed an environmental load estimation model that can be used at the early stage of the project using basic design factors. The model was constructed by using the artificial neural network to estimate environmental load by applying to planning stage (ANN-1), basic design stage (ANN-2). The result of test, shows that average of absolute measuring efficiency and standard deviation of ANN-1 and ANN-2 were 11.19% / 5.30% and 9.59% / 3.09% each. This result indicates that the model using the input variables extended with the project progress has high reliability and it is considered to be effective in decision support at the initial design stage of the project.

• Journal of the Korea Computer Industry Society
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• v.3 no.3
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• pp.295-306
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• 2002

Successful project planning relies on a good estimation of the effort required to complete a project, together with the schedule options that may be available. Despite the extensive research done developing new and better models, existing software effort estimation models are present only the total effort and instantaneous effort function for the software life-cycle. Also, Putnam presents constant effort rate in each phase. However, the size of total effort are variable according to the software projects under the influence of its size, complexity and operational environment. As a result, the allocated effort in each phase also differ from project to project. This paper suggests the criteria for effort allocation in planning, specifying, building, testing and implementing phase followed by the project total effort. These criteria are derived from 183 different projects. This result can be considered as a practical guideline in management of project schedule and effort allocation.