• Title/Summary/Keyword: Plant Projects

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Q-learning for tunnel excavation schedule

  • Shuhan YANG;Ke DAI;Zhihao REN;Jung In KIM;Bin XUE;Dan WANG;Wooyong JUNG
    • International conference on construction engineering and project management
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    • 2024.07a
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    • pp.799-806
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    • 2024
  • Construction planners for hard rock tunnel projects often encounter practical challenges caused by inherent uncertainties in ground conditions and resource constraints. Therefore, planners cannot rapidly generate optimal excavation schedules for the shortest project durations with a given equipment fleet by considering the uncertainties in ground conditions. Although some schedule optimization methods exist, they are not tailored for resource-constrained hard rock tunnel projects. To overcome these limitations, the authors specified a formal Q-learning-based schedule optimization methodology for resource-constrained hard rock tunnel projects. States are defined according to the locations of tunnel faces under excavation. Actions consist of multiple and comprehensive heuristic-based rules, which are efficient methods for resource allocation. Rewards are the time intervals required between current states and next states. After that, the methodology is validated using a case study. The generated Q tables indicate (1) best actions under different states and (2) the shortest remaining durations when the project starts from specific (state, action) pairs. The results demonstrate that the optimal schedules can be obtained by applying the proposed methodology. Furthermore, it is beneficial for planners to rapidly assign optimal rules for each state under one ground condition scenario. The results further show the potential to consider the uncertainties in ground conditions using the information of possible ground condition scenarios provided.

Reinforced-Concrete Works Productivity and Influence Factor Analysis on Nuclear-Power-Plant Project (원자력발전소 건설현장의 철근콘크리트 공종 생산성 및 영향요인 분석)

  • Huh, Young-Ki;Lim, Jin-Ho;Kim, Kyoung-Uk;Ahn, Young-Chul;Oh, Jae-Hun
    • Journal of the Korea Institute of Building Construction
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    • v.14 no.4
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    • pp.314-321
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    • 2014
  • Nuclear power plant projects are being increased all over the world. The construction of nuclear power plants needs huge money and time, which makes conducting a detailed analysis of productivity through the whole process. Reinforced-concrete works productivity field data was collected for more than one year and analyzed from a nuclear-power-plant project in Korea. The productivities of formwork, rebar-work, and concrete pouring were $0.54m^2/man{\cdot}day$, $0.06ton/man{\cdot}day$, $1.98m^3/man{\cdot}day$, respectively. Moreover, it is revealed that 'Day of the Week' is a driver of the formwork activity and 'Overtime' is for all of the three. The results will be a great interest of industry personnel estimating time and cost of a new nuclear power plant.

Proposal for Developed Procurement and Material management System On Using Previous System Analysis in Plant Engineering (플랜트 구매조달 및 자재관리 시스템 개발 요구사항 분석을 통한 개발 방향 제시)

  • Lee, Seung-Hun;Kim, Sun-Kuk;Lee, Jun-Bok;Han, Choong-Hee
    • Proceedings of the Korean Institute Of Construction Engineering and Management
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    • 2006.11a
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    • pp.204-209
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    • 2006
  • Despite the recent depression of the construction industry, overseas plant market especially Middle East plant market is booming owing to the high oil price. Since many Middle Eastern countries are placing orders of big scale projects based on the high oil price, Korean EPC contractor are trying to get over the depression through theses plants. Presently, since the plant market is in prosperous condition in general, it is not hard to get overseas orders; however the original licenses that requirehigher technology and high added values are exclusive for advanced engineering companies which great difficulty is predicted for developing countries like us to join the crowd. Therefore, the objective of this study is to propose establishment of material management system on the filed to gain optimized effect of material management in connection with procurement system that all the procurement related personals execute tasks in advanced level by systemizing the task operation within the knowledge and task ability in time for plant construction procurement as a method to strengthening the competitiveness of Korean companies.

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Critical Success Factors for Nuclear Power Plant Construction Projects (원전건설의 성공적인 시공을 위한 핵심성공요인(CSFs) 도출)

  • Shin, Gisung;Bang, Seongdeok;Kim, Kyeongseok;Kim, Hyoungkwan
    • Korean Journal of Construction Engineering and Management
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    • v.18 no.1
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    • pp.48-57
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    • 2017
  • The construction of the first nuclear power plant (Kori #1) in Korea started in 1971, Korea operates 24 nuclear power plants and is constructing 4 in 2015. During about 45 years of construction experience, insufficient studies have been investigated for the identification of critical success factors(CSFs) for nuclear power plant construction. Based on literature reviews and focus group interviews, this study presented a list of CSFs for construction of nuclear power plants. A survey for validating the results of CSFs was conducted with 164 experts. This study indicates that attentions should be placed upon the lowest price-based contract awarding policy, the need for reasonable pricing standard implementation, database development, and deployment for experienced nuclear power plant construction workers, identification and nurturing of competitive subcontractors, and minimization of lag times in construction activities.

The Impact of Side Reactions in Sulfur Recovery Unit Design (황 회수 공정 설계에서 부 반응의 영향)

  • Kim, Sung Ho;Jung, Won Seok;Lee, Hee Mun;Chang, Geun Soo
    • Plant Journal
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    • v.13 no.3
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    • pp.36-46
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    • 2017
  • In the reaction furnace of modified Claus process, chemical equilibrium reactions and kinetic reactions occur simultaneously. The main kinetic components are hydrogen ($H_2$), carbon monoxide (CO), carbonyl sulphide (COS) and carbon disulphide ($CS_2$). The equilibrium calculations, empirical correlations and sulfur recovery technology providers' (licensors) data for kinetic components (COS and $CS_2$) in the reaction furnace were analyzed to evaluate the amount of kinetic components by applying them to five different projects in which GS Engineering & Construction participated. Kinetic components ($H_2$ and CO) are also calculated and the results are analyzed to evaluate the impact of temperature in the reaction furnace and the waste heat boiler. Total required $O_2$ deviations for combustion in the reaction furnace are additionally shown, with and without side reactions. A full understanding of side reactions in the modified Claus process can help to improve sulfur recovery efficiency and optimize equipment design.

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A Study on Actual Condition of Topsoil Management at Forest Development Projects (산지개발사업에서 표토관리 실태에 관한 연구)

  • Kim, Won Tae;Cho, Yong Hyeon;Lee, Jong Mun;Yoon, Yong Han;Kang, Hee Kyoung;Park, Bong Ju;Yoon, Taek Seong;Jang, Kwang Eun;Shin, Kyung Jun;Eo, Yang Joon;Kwak, Moo Young;Song, Hong Seon
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.17 no.1
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    • pp.13-25
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    • 2014
  • The study aims to investigate and analyze actual situations of managing topsoil at forest development sites based on their types, in pursuit of conservation and effective use of national land. To do this, I selected target areas by deducting the typical types of forest development and analyzed the condition of soil at the target areas before and after development. In addition to this, I interviewed associated construction staffs to conduct study on present situations of topsoil management and find out its problems. I also surveyed of relevant experts, with the intention of seeking solutions. The results of the study have been shown that firstly, experts preferred collecting and recycling of topsoil as methods of improvement of soil conditions for plant growth. Secondly, the importance of topsoil has been well noticed and there were few construction sites using the methods. However, working and economical problems have disturbed carrying out these solutions. Thirdly, after constructions, organic matter and total-nitrogen content decreased in general which were necessary for plant growth in terms of soil conditions.

Analysis of genome variants in dwarf soybean lines obtained in F6 derived from cross of normal parents (cultivated and wild soybean)

  • Roy, Neha Samir;Ban, Yong-Wook;Yoo, Hana;Ramekar, Rahul Vasudeo;Cheong, Eun Ju;Park, Nam-Il;Na, Jong Kuk;Park, Kyong-Cheul;Choi, Ik-Young
    • Genomics & Informatics
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    • v.19 no.2
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    • pp.19.1-19.9
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    • 2021
  • Plant height is an important component of plant architecture and significantly affects crop breeding practices and yield. We studied DNA variations derived from F5 recombinant inbred lines (RILs) with 96.8% homozygous genotypes. Here, we report DNA variations between the normal and dwarf members of four lines harvested from a single seed parent in an F6 RIL population derived from a cross between Glycine max var. Peking and Glycine soja IT182936. Whole genome sequencing was carried out, and the DNA variations in the whole genome were compared between the normal and dwarf samples. We found a large number of DNA variations in both the dwarf and semi-dwarf lines, with one single nucleotide polymorphism (SNP) per at least 3.68 kb in the dwarf lines and 1 SNP per 11.13 kb of the whole genome. This value is 2.18 times higher than the expected DNA variation in the F6 population. A total of 186 SNPs and 241 SNPs were discovered in the coding regions of the dwarf lines 1282 and 1303, respectively, and we discovered 33 homogeneous nonsynonymous SNPs that occurred at the same loci in each set of dwarf and normal soybean. Of them, five SNPs were in the same positions between lines 1282 and 1303. Our results provide important information for improving our understanding of the genetics of soybean plant height and crop breeding. These polymorphisms could be useful genetic resources for plant breeders, geneticists, and biologists for future molecular biology and breeding projects.

The Status and Prospect of CTL (Coal-to-Liquid) (CTL(Coal-to-Liquid) 기술 현황)

  • Jung, Heon;Yang, Jung-Il;Kim, Hak-Joo;Chun, Dong-Hyun
    • Journal of Energy Engineering
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    • v.16 no.2
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    • pp.64-72
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    • 2007
  • During the 2nd World War, several Coal-to-Liquid (CTL) plants were operated in Germany and England to convert coal to large volumes of liquid fuel. Big oil fields discovered in the Middle East after the war supplied crude oil at the low price and all CTL plants were forced to shut down. However, South Africa (Sasol) built a CTL plant in 1955 and 2 more plants afterward and the current production of coal-derived synfuel reached 150,000 bbl/day. Recently, the sustained high crude oil price and the fear of the "peak oil" rejuvenated the interest of CTL and several CTL projects are in progress. China established a plan to build CTL plants with the total capacity of 30 million tons of synfuel per year by 2030. China is building a direct coal liquefaction plant which is scheduled to produce 20,000bbl/day of synfuel in 2008. There are 8 CTL projects in USA either in the planning stage or in the ground-breaking stage. CTL projects are also carried out in Australia, Philippines, New Zealand, Indonesia and India. Korea needs to approach the CTL project in the perspective of the national energy security. In this paper, the history, the status, current activities and the prospect of CTL are described.

Analyzing Site Reliability for Residential, Civil and Plant Projects using Lean Construction Principles (린 건설에 기초한 국내 건설 공사의 시공 계획 신뢰도 평가 및 분석)

  • Koo, Bonsang
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.28 no.5D
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    • pp.655-664
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    • 2008
  • Lean Construction recommends implementing site production management by measuring the reliability of daily production tasks, collecting the causes for failure of incomplete tasks, and identifying problems in the existing process based on the collected data. Although many research projects have been performed to introduce Lean Construction in Korea, there are not many cases in which day-to-day site production operations has been stringently evaluated based on such methods. This paper introduces three cases in which such techniques were implemented on a residential, civil infrastructure and plant project. On each project, process maps were created with the superintendents and daily production meetings were held for two weeks. Consequently, the average PPC for the three projects was 79% for PPC and 16% for PAT. In addition, the majority of the failures were due to 'Directive/Plan' and 'Prerequisites.' The results show that project stakeholders (owners, contractors, etc.) lack the ability to plan ahead and keep to their plans, and also lack the capability to synchronize workflow between themselves. The results also reveal that project participants need to be more proactive in solving process problems on site and also need to be better educated in Lean concepts and methodologies.

A Study on the Current Status of Ecological Restoration Plant Species Use - Focusing on the Ecosystem Conservation Cooperation Fund Return Projects - (생태복원 식물종 사용 실태에 관한 연구 - 생태계보전협력금 반환사업을 중심으로 -)

  • Cho, Dong-gil
    • Korean Journal of Environment and Ecology
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    • v.35 no.5
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    • pp.525-547
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    • 2021
  • The main purpose of this study is to examine the use of plant species in ecological restoration projects. To this end, planting drawings from 58 sites that had completed the return of the ecosystem conservation cooperation fund for the past six years were collected and analyzed. The analysis used the construction completion and design drawings to determine the overall selection status and analyze frequency by classifying planted plants into wild and cultivated plants by nature, size, vegetation climate, and upland and wetland habitat. The investigation and analysis process found many cases of wrong plant names, so an analysis was also performed on the matter. In the 58 investigation sites, 282 plants were used for planting: 91 tree species, 69 shrub species, 11 vine species, and 111 herbal species. The most commonly used plant species was Spiraea prunifolia f. simpliciflora, followed by Sorbus alnifolia, Quercus acutissima, Zoysia japonica, Callicarpa dichotoma, and Weigela subsessilisin that order. The most commonly used tree species was Sorbus alnifolia,followed by Quercus acutissima, Zelkova serrata, Chionanthus retusus, and Cornus officinalis, in that order. The most commonly used shrub species was Spiraea prunifolia f. simpliciflora, followed by Weigela subsessilis, Callicarpa dichotoma, Rhododendron yedoense f. poukhanense. and Euonymus alatusin that order. The most commonly used herbal plant species was Zoysia japonica, followed by Dendranthema zawadskii var. latilobum, Aster koraiensis, Miscanthus sacchariflorus, and Pennisetum alopecuroidesin that order. In the analysis by vegetation climate, Spiraea prunifolia f. simpliciflora, Callicarpa dichotoma, and Sorbus alnifoliawere most used in that order in both the temperate central and the warm temperate forest zones, but the pattern does not properly reflect the climate characteristics. In the analysis by habitat, Miscanthus sacchariflorus and Lythrum salicariawere most used in the wetland. In particular, the ratio of wild plants to cultivated plants was 76% to 24%, indicating the ratio of selecting cultivated plants was high. The names of plants on the drawings were mostly common names that did not appear in the Korea National Arboretum or the National Species List of Korea. It is necessary to use proper plant names in the future. Regarding the use of planting plants for ecological restoration, it is necessary to adopt the approach of diversifying selected plants, selecting plants according to characteristics of climate zones, and lowering the specifications of plants used for ecological restoration. Moreover, it is important to fully understand the ecological characteristics of wetland plants and minimize the ratio of using cultivated plants to ensure the plant selection centered on wild plants.