• Title/Summary/Keyword: Introduction to Engineering Design

Search Result 461, Processing Time 0.023 seconds

Rational Building Energy Assessment using Global Sensitivity Analysis (전역 민감도 분석을 이용한 건물 에너지 성능평가의 합리적 개선)

  • Yoo, Young-Seo;Yi, Dong-Hyuk;Kim, Sun-Sook;Park, Cheol-Soo
    • Journal of the Architectural Institute of Korea Structure & Construction
    • /
    • v.36 no.5
    • /
    • pp.177-185
    • /
    • 2020
  • The building energy performance indicator, called Energy Performance Index (EPI), has been used for the past decades in South Korea. It has a list of design variables assigned with weighting factors (a, b). Unfortunately, the current EPI method is not performance-based but very close to a prescriptive rating. With this in mind, this study aims to propose a new performance-based EPI method. For this purpose, a global sensitivity analysis method, Sobol, is employed. The Sobol method is suitable for complex nonlinear models and can decompose all the output variance due to every input. The Sobol sensitivity index of each variable is defined as 0 to 1 (0 to 100%), and the sum of all sensitivity indices is equal to 1 (100%). In this study, an office building was modeled using EnergyPlus and then the Latin Hypercube Sampling (LHS) was conducted to generate a surrogate model to EnergyPlus. The sensitivity index was suggested to replace weight (a) in the existing EPI. In addition, the discrete weight (b) in the existing EPI was replaced by a set of continuous regression functions. Due to the introduction of the sensitivity index and the continuous regression functions, the new proposed approach can provide far more accurate outcome than the existing EPI (R2: 0.83 vs. R2: 0.01 for cooling, R2: 0.66 vs. R2: 0.01 for total energy). The new proposed approach proves to be more rational, objective and performance-based than the existing EPI method.

Estimation of Harbor Responses due to Construction of a New Port in Ulsan Bay

  • Lee, Joong-Woo;Lee, Hoon;Lee, Hak-Seung;Jeon, Min-Su
    • Journal of Navigation and Port Research
    • /
    • v.28 no.7
    • /
    • pp.619-627
    • /
    • 2004
  • Introduction of wave model, considered the effect of shoaling, refraction, diffraction, partial reflection, bottom friction, breaking at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster prevention problems. As waves move from deeper waters to shallow coastal waters, the fundamental wave parameters will change and the wave energy is redistributed along wave crests due to the depth variation, the presence of islands, coastal protection structures, irregularities of the enclosing shore boundaries, and other geological features. Moreover, waves undergo severe change inside the surf zone where wave breaking occurs and in the regions where reflected waves from coastline and structural boundaries interact with the incident waves. Therefore, the application of mild-slope equation model in this field would help for understanding of wave transformation mechanism where many other models could not deal with up to now. The purpose of this study is to form a extended mild-slope equation wave model and make comparison and analysis on variation of harbor responses in the vicinities of Ulsan Harbor and Ulsan New Port, etc. due to construction of New Port in Ulsan Bay. We also considered the increase of water depth at the entrance channel by dredging work up to 15 meters depth in order to see the dredging effect. Among several model analyses, the nonlinear and breaking wave conditions are showed the most applicable results. This type of trial might be a milestone for port development in macro scale, where the induced impact analysis in the existing port due to the development could be easily neglected.

A Study on RFID System Design and Expanded EPCIS Model for Manufacturing Systems (제조 시스템의 RFID System 설계 및 EPCIS 확장모형 연구)

  • Choi, Weon-Yong;Lee, Jong-Tae
    • Journal of the Korea Safety Management & Science
    • /
    • v.9 no.6
    • /
    • pp.123-135
    • /
    • 2007
  • In the recent years, the companies have manually recorded a production status in a work diary or have mainly used a bar code in order to collect each process's progress status, production performance and quality information in the production and logistics process in real time. But, it requires an additional work because the worker's record must be daily checked or the worker must read it with the bar code scanner. At this time, data's accuracy is decreased owing to the worker's intention or mistake, and it causes the problem of the system's reliability. Accordingly, in order to solve such problem, the companies have introduced RFID which comes into the spotlight in the latest automatic identification field. In order to introduce the RFID technology, the process flow must be analyzed, but the ASME sign used by most manufacturing companies has the difficult problem when the aggregation event occurs. Hence, in this study, the RFID logistic flow analysis Modeling Notation was proposed as the signature which can analyze the manufacturing logistic flow amicably, and the manufacturing logistic flow by industry type was analyzed by using the proposed RFID logistic flow analysis signature. Also, to monitor real-time information through EPCglobal network, EPCISEvent template by industry was proposed, and it was utilized as the benchmarking case of companies for RFID introduction. This study suggested to ensure the decision-making on real-time information through EPCglobal network. This study is intended to suggest the Modeling Notation suitable for RFID characteristics, and the study is intended to establish the business step and to present the vocabulary.

Improvement of Quantity Take-Off and BoQ through the LOD Criteria Analysis of BIM Models (BIM 모델 표현 수준(LOD) 분석을 통한 내역체계 개선방안 연구)

  • Choi, Hyunjun;Yun, Seokheon
    • Korean Journal of Construction Engineering and Management
    • /
    • v.20 no.6
    • /
    • pp.89-97
    • /
    • 2019
  • Recently, BIM has been actively introduced in construction projects. In particular, the introduction of BIM in cost estimating process is expected to improve the accuracy and efficiency of the cost estimate. However, the quantity calculation and BoQ documents preparation process still require manual work. Although the BIM model may support quantification process, it is still problematic that the level of detail of the model must be very detailed to meet the items in BoQ. To address this, it is necessary to analyse the LOD criteria and to analyze the extent to which quantity can be computed according to the level of detail in the BIM model. For the analysis of LOD-based work items, the work item grades were divided into A,B, and C. In this study, the ratio and cost of each item that can be calculated at the LOD level in the detailed design phase are reviewed for each type of work, and the method for improving the quantity calculation using BIM is proposed. In the LOD 300 stage(Detailed design stage), the largest number of items in the class B, the major improvement class, are window and glass work. In addition, the most expensive type of work was analyzed by reinforced concrete work. In the future, it is necessary to suggest appropriate improvement way for items with high item ratios and items with high cost ratios. The results of this study are expected to be used as a BIM-based cost estimation or as basic data for improving the current BoQ system.

Evaluation of the limit ice thickness for the hull of various Finnish-Swedish ice class vessels navigating in the Russian Arctic

  • Kujala, Pentti;Korgesaar, Mihkel;Kamarainen, Jorma
    • International Journal of Naval Architecture and Ocean Engineering
    • /
    • v.10 no.3
    • /
    • pp.376-384
    • /
    • 2018
  • Selection of suitable ice class for ships operation is an important but not simple task. The increased exploitation of the Polar waters, both seasonal periods and geographical areas, as well as the introduction of new international design standards such as Polar Code, reduces the relevancy of using existing experience as basis for the selection, and new methods and knowledge have to be developed. This paper will analyse what can be the limiting ice thickness for ships navigating in the Russian Arctic and designed according to the Finnish-Swedish ice class rules. The permanent deformations of ice-strengthened shell structures for various ice classes is determined using MT Uikku as the typical size of a vessel navigating in ice. The ice load in various conditions is determined using the ARCDEV data from the winter 1998 as the basic database. By comparing the measured load in various ice conditions with the serviceability limit state of the structures, the limiting ice thickness for various ice classes is determined. The database for maximum loads includes 3-weeks ice load measurements during April 1998 on the Kara Sea mainly by icebreaker assistance. Gumbel 1 distribution is fitted on the measured 20 min maximum values and the data is divided into various classes using ship speed, ice thickness and ice concentration as the main parameters. Results encouragingly show that present designs are safer than assumed in the Polar Code suggesting that assisted operation in Arctic conditions is feasible in rougher conditions than indicated in the Polar Code.

Effects of load variation on a Kaplan turbine runner

  • Amiri, K.;Mulu, B.;Cervantes, M.J.;Raisee, M.
    • International Journal of Fluid Machinery and Systems
    • /
    • v.9 no.2
    • /
    • pp.182-193
    • /
    • 2016
  • Introduction of intermittent electricity production systems like wind and solar power to electricity market together with the deregulation of electricity markets resulted in numerous start/stops, load variations and off-design operation of water turbines. Hydraulic turbines suffer from the varying loads exerted on their stationary and rotating parts during load variations since they are not designed for such operating conditions. Investigations on part load operation of single regulated turbines, i.e., Francis and propeller, proved the formation of a rotating vortex rope (RVR) in the draft tube. The RVR induces pressure pulsations in the axial and rotating directions called plunging and rotating modes, respectively. This results in oscillating forces with two different frequencies on the runner blades, bearings and other rotating parts of the turbine. This study investigates the effect of transient operations on the pressure fluctuations exerted on the runner and mechanism of the RVR formation/mitigation. Draft tube and runner blades of the Porjus U9 model, a Kaplan turbine, were equipped with pressure sensors for this purpose. The model was run in off-cam mode during different load variations. The results showed that the transients between the best efficiency point and the high load occurs in a smooth way. However, during transitions to the part load a RVR forms in the draft tube which induces high level of fluctuations with two frequencies on the runner; plunging and rotating mode. Formation of the RVR during the load rejections coincides with sudden pressure change on the runner while its mitigation occurs in a smooth way.

Management Research in Plant Construction;Introduction of research center (플랜트 프로젝트 관리체계 표준화 기술 개발;연구단 소개)

  • Lee, Young-Nam;Kim, Chan-Soo
    • Proceedings of the Korean Institute Of Construction Engineering and Management
    • /
    • 2006.11a
    • /
    • pp.213-220
    • /
    • 2006
  • Plant construction industry is a high value-adding industry because it is complex industry comprising engineering, procurements of equipments and construction. So, Revenue increase in overseas plant projects would boost up not only domestic construction industry but also growth of national economy. Recently, overseas plant-construction market is expanding dramatically. For instant, Middle-east countries are constantly increasing their orders for the construction of petro-chemical plants stimulated by sky-rocketing oil prices. The purpose of this research is to develop management techniques for plant projects such as work break-down structure, knowledge management system, logistics & procurement system, and risk assessment tools. We believe our research would contribute to the competion of Korean engineeing companies and contractors in overseas plant-construction market.

  • PDF

Estimation of Harbor Responses due to Construction of a New Port in Ulsan Bay

  • Lee, Joong-Woo;Lee, Hoon;Lee, Hak-Sung;Jeon, Min-Su
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
    • /
    • 2004.08a
    • /
    • pp.217-225
    • /
    • 2004
  • Introduction of wave model, considered the effect of shoaling, refraction, diffraction, partial reflection, bottom friction, breaking at the coastal waters of complex bathymetry, is a very important factor for most coastal engineering design and disaster prevention problems. As waves move from deeper waters to shallow coastal waters, the fundamental wave parameters will change and the wave energy is redistributed along wave crests due to the depth variation, the presence of islands, coastal protection structures, irregularities of the enclosing shore boundaries, and other geological features. Moreover, waves undergo severe change inside the surf zone where wave breaking occurs and in the regions where reflected waves from coastline and structural boundaries interact with the incident waves. Therefore, the application of mild-slope equation model in this field would help for understanding of wave transformation mechanism where many other models could not deal with up to now. The purpose of this study is to form a extended mild-slope equation wave model and make comparison and analysis on variation of harbor responses in the vicinities of Ulsan Harbor and Ulsan New Port, etc. due to construction of New Port in Ulsan Bay. This type of trial might be a milestone for port development in macro scale, where the induced impact analysis in the existing port due to the development could be easily neglected.

  • PDF

Estimation of Reliability Level and Applicability of LRFD Based on Standard Drawings of Railway Cantilever Retaining Walls (철도 옹벽 표준도의 신뢰도수준 및 LRFD 적용성 평가)

  • Kim, In-Soo;Lim, Heui-Dae;Park, Joon-Mo
    • Journal of the Korean Geotechnical Society
    • /
    • v.31 no.10
    • /
    • pp.61-76
    • /
    • 2015
  • Recently, geotechnical engineering researches have been conducted on the Limit State Design (LSD) for deep and shallow foundations; however, there are very few studies on the retaining wall. As a basic study for the introduction of the LSD of a railway retaining wall, this study evaluates whether the reliability index satisfies the target reliability index for each failure mode in the standard drawing of the retaining wall. It also analyzes the feasibility of the LSD method by using the Load and Resistance Factor Design (LRFD) for the standard drawing of a retaining wall. In a portion of the standard drawing of the railway retaining wall, the reliability indices of the sliding and bearing capacity failure modes did not satisfy the target reliability index, and could not satisfy the limit state by the LRFD. Hence, the standard drawing of the railway retaining wall will need to be revised if the LSD is to be applied.

Comparison of Construction Cost Applied by RC and PC Construction Method for Apartment House and Establishment of OSC Economic Analysis Framework (공동주택 RC 및 PC공법 적용 공사비 비교 및 OSC의 포괄적 경제성 분석 프레임워크 구축)

  • Yun, Won-Gun;Bae, Byung-Yun;Kang, Tai-Kyung
    • Korean Journal of Construction Engineering and Management
    • /
    • v.23 no.6
    • /
    • pp.30-42
    • /
    • 2022
  • OSC is a type of supply chain and value chain that spans the entire process of construction production (planning, design, construction, maintenance, etc.). It is a method of producing the final object by manufacturing it in a factory, transporting it to the site, installing and construction. This research as is the construction cost was compared for each case A, which applied the PC method, and case B, which applied the RC method. In the case of applying the PC method (excluding the PC design cost), compared to the case where only the RC method was applied, the frame construction cost per unit quantity (m3) increased by about 70% (50% based on the total RC construction type). Of the total frame construction cost of PC method application, PC accounted for 90.2%, 'PC manufacturing cost' 54.8%, 'PC assembly cost' 28.5%, and 'transportation cost' accounted for 6.89%. Also a decision-making framework that can consider both costs and benefits was established. In the case of benefits, the construction period, defect repair, disaster occurrence, energy efficiency, noise/dust/waste, and greenhouse gas emission indicators reflecting OSC technical advantages were presented. It can contribute to providing a basis for helping decision-making on the introduction of PC apartment houses using OSC.