• 제목/요약/키워드: Loss Estimation

검색결과 1,101건 처리시간 0.029초

Computer-Aided Optimal Design of Heat Exchangers (컴퓨터에 의한 열교환기 최적설계)

  • Song Tae Ho;Oh Jin Kook;Yoon Chang Hyun;Huh Gyoung Jae
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • 제10권4호
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    • pp.297-303
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    • 1981
  • Optimal design of shell and tube heat exchanger system with the working fluids which may condense outside the tubes has been carried out under specified inlet and outlet conditions. Independent variables such as number of parallel series, tube diameter, distribution pitch, tube side pressure loss, baffle cut and shell side pressure loss as well as dependent variables such as shell diameter, number of tubes, number of serial series and number of baffles were all characterized according to the standard. Exhaustive search method was used to construct a computer program together with the calculation of heat transfer rate by LMTD method. stress analysis of maj or parts was made to examine their dimensions satisfying heat transfer and pressure loss requirements. Cost estimation based on the installation, operation and maintenance was also made, A few representative variables, heat transfer area, shell diameter and pressure loss, were used to express cost function, finally giving the optimal selection of all tentative solutions.

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Los Angeles Abrasion Test for Estimating Engineering Index on the Sedimentary Rocks of Kyeongsang Basin (퇴적암의 공학지수를 추정하기 위한 L. A. 마모율 시험)

  • Min, Tuk-Ki;Moon, Jong-Kyu;Lee, Sang-Il
    • Journal of the Korean Geotechnical Society
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    • 제23권11호
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    • pp.15-26
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    • 2007
  • Los Angeles abrasion loss test has usally been applied to the quarry for the purpose of aggregate hardness estimation. 324 blocks from 25 sites of Kyeongsang basin samples of sedimentary rock were examined and tested in laboratary. This paper found that L. A. abrasion loss test is a good method to estimate engineering index such as uniaxial compressive strength, elastic modulus, indirect tensile strength, point load strength index, Schmidt hammer rebound value of sedimentary rocks with high correlation factor. Engineers will prefer L. A. abrasion loss test to the other one for design and construction as this method is quick and easy.

Transient loss analysis of non-insulation high temperature superconducting coil using the field-based data profiling method

  • Hoon Jung;Yoon Seok Chae;June Hee Han;Ji Hyung Kim;Seung Hoon Lee;Ho Chan Kim;Young Soo Yoon;Ho Min Kim
    • Progress in Superconductivity and Cryogenics
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    • 제25권3호
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    • pp.38-42
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    • 2023
  • The evaluation of no-insulation (NI) high-temperature superconducting (HTS) typically uses the lumped equivalent circuit (LEC) model. Constant parameters in the NI HTS LEC model accurately predict voltage and central magnetic field at currents below the critical current. However, it is difficult to find constant circuit parameters that simultaneously satisfy the measured voltage and magnetic field under overcurrent conditions. Recent research highlights changes in contact resistance during transient conditions, which may impact power loss estimation in NI HTS coils. Therefore, we confirm the influence of contact resistance changes on loss calculation in the transient state for NI HTS coil. To achieve this, we introduce a measurement data analysis method based on the LEC model and compare it with the LEC model using constant circuit parameters.

Classical and Bayesian inferences of stress-strength reliability model based on record data

  • Sara Moheb;Amal S. Hassan;L.S. Diab
    • Communications for Statistical Applications and Methods
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    • 제31권5호
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    • pp.497-519
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    • 2024
  • In reliability analysis, the probability P(Y < X) is significant because it denotes availability and dependability in a stress-strength model where Y and X are the stress and strength variables, respectively. In reliability theory, the inverse Lomax distribution is a well-established lifetime model, and the literature is developing inference techniques for its reliability attributes. In this article, we are interested in estimating the stress-strength reliability R = P(Y < X), where X and Y have an unknown common scale parameter and follow the inverse Lomax distribution. Using Bayesian and non-Bayesian approaches, we discuss this issue when both stress and strength are expressed in terms of lower record values. The parametric bootstrapping techniques of R are taken into consideration. The stress-strength reliability estimator is investigated using uniform and gamma priors with several loss functions. Based on the proposed loss functions, the reliability R is estimated using Bayesian analyses with Gibbs and Metropolis-Hasting samplers. Monte Carlo simulation studies and real-data-based examples are also performed to analyze the behavior of the proposed estimators. We analyze electrical insulating fluids, particularly those used in transformers, for data sets using the stress-strength model. In conclusion, as expected, the study's results showed that the mean squared error values decreased as the record number increased. In most cases, Bayesian estimates under the precautionary loss function are more suitable in terms of simulation conclusions than other specified loss functions.

Assessment of Soil Loss at Military Shooting Range by RUSLE Model: Correlation Between Soil Loss and Migration of Explosive Compounds (RUSLE 모델에 의한 군사격장 피탄지 토양유실량 평가: 토양 유실과 오염 화약물질 이동 상관성)

  • Gong, Hyo-Young;Lee, Kwang-Pyo;Lee, Jong-Yeol;Kim, Bumjoon;Lee, Ahreum;Bae, Bumhan;Kim, Ji-Yeon
    • Journal of Soil and Groundwater Environment
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    • 제17권6호
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    • pp.119-128
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    • 2012
  • The applicability and accuracy of Revised Universal Soil Loss Equation (RUSLE) model on the estimation of soil loss at impacted area of shooting range was tested to further the understanding of soil erosion at shooting ranges by using RUSLE. At a shooting range located in northern Kyunggi, the amount of soil loss was estimated by RUSLE model and compared with that estimated by Global Positioning System-Total Station survey. As results, the annual soil loss at a study site (202 m long by 79 m wide) was estimated to be 2,915 ton/ha/year by RUSLE and 3,058 ton/ha/year by GPS-TS survey, respectively. The error between two different estimations was less than 5%, however, information on site conditions should be collected more to adjust model coefficients accurately. At the study shooting range, sediments generated by rainfall was transported from the top to near the bottom of the sloping face through sheet erosion as well as rill erosion, forming a gully along the direction of the storm water flow. Coarser fractions of the sediments were redeposited in the limited area along the channel. Distribution characteristics of explosive compounds in soil before and after summer monsoon rainfall in the study area were compared with the erosion patterns. Soil sampling and analyses results showed that the dispersion of explosive compounds in surface soil was consistent with the characteristics of soil erosion and redeposition pattern of sediment movements after rainfalls.

A study on estimation of the total loss and damage ratio of maintenance monitoring sensor of subway tunnel (지하철 터널 유지관리 계측센서의 총 손망실율 산정 연구)

  • Woo, Jong-Tae
    • Journal of Korean Tunnelling and Underground Space Association
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    • 제15권1호
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    • pp.25-31
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    • 2013
  • In this study, the total loss and damage ratio of maintenance monitoring which is installed and operated in the domestic and foreign tunnel structure is researched and analyzed for estimating the loss and damage ratio of maintenance monitoring sensor of subway tunnel. The total loss and damage ratio at the elapsed time of 5-6 years after installation is 14.2% in the Seoul metro line no.5,6 and 7, 14.8% in the section 1 of the Seoul metro line no.9, 13.9% in the Channel tunnel of England and all of them are close to 15%. Therefore, it is reasonable to reflect that the total loss and damage ratio of maintenance monitoring sensor of subway tunnel is estimated provisionally 15% on design, and hence the study of the loss and damage ratio with the number of elapsed years in long-term by the measurement category will be needed.

A Study on the Temporal Change of Soil Loss of Kyungan River Basin with GIS (토지이용변화에 따른 경안천 유역 토양유실에 관한 연구)

  • 김상욱;박종화
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • 한국GIS학회 1995년도 추계학술대회 발표요약문
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    • pp.22-32
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    • 1995
  • The purpose of this study is to estimate not only the watershed soil loss but also its temporal changes of Kyungan River basin, the study area, due to the land development. To analyze the soil loss of the river basin, USLE was employed. GIS and remote sensing were also utilized to estimate the soil loss. The data for this analysis consist of a series of thematic map and remotely sensed data. The remotely sensed images for this study are Landsat TM(Oct, 28, 1997 & Sep. 22, 1992), In Kyungan River basin, not only the detection of temporal changes of land use and GVI, but also the estimation of soil loss provided very significant factors that affect to the watershed environment quality. The management of the factors of vegetative cover, slope steepness and length were the keys to reduce soil loss and solve conservation and protection issues of Kyungan River basin. GIS application with USLE to the watershed analysis allows the planner to recognize sensitive sites and to plan strategies to minimize soil loss.

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Impact of Channel Estimation Errors on SIC Performance of NOMA in 5G Systems (5G 시스템에서 비직교 다중접속의 SIC 성능에 대한 채널 추정 오류의 영향)

  • Chung, Kyuhyuk
    • Journal of Convergence for Information Technology
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    • 제10권9호
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    • pp.22-27
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    • 2020
  • In the fifth generation (5G) networks, the mobile services require much faster connections than in the fourth generation (4G) mobile networks. Recently, as one of the promising 5G technologies, non-orthogonal multiple access (NOMA) has been drawing attention. In NOMA, the users share the frequency and time, so that the more users can be served simultaneously. NOMA has several superiorites over orthogonal multiple access (OMA) of long term evolution (LTE), such as higher system capacity and low transmission latency. In this paper, we investigate impact of channel estimation errors on successive interference cancellation (SIC) performance of NOMA. First, the closed-form expression of the bit-error rate (BER) with channel estimation errors is derived, And then the BER with channel estimation errors is compared to that with the perfect channel estimation. In addition, the signal-to-noise (SNR) loss due to channel estimation errors is analyzed.

A Study on Awareness to Effectiveness of the Cost Estimation Guidelines for e-Learning Content Development in Era of Convergence (융합시대의 이러닝 콘텐츠 개발대가 산정 가이드라인의 실효성에 관한 인식 연구)

  • Noh, Kyoo-Sung
    • Journal of Digital Convergence
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    • 제13권11호
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    • pp.7-14
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    • 2015
  • The purpose of this study is to present the base for activation policy for cost estimation guidelines of e-Learning content development. To achieve this purpose, this study investigates the effectiveness of cost estimation guidelines of e-Learning content development through a survey about executives and employees in the e-Learning industry and analyses them statistically. According to an analysis, companies(which abandoned order because the amount of money (cost) of e-Learning contents ordering is low and suffered a loss after acquiring e-Learning contents project order) have a relatively negative awareness about the effectiveness of cost estimation guidelines of e-Learning contents. On the other hand, contents focused companies have a relatively positive awareness about the effectiveness of cost estimation guidelines of e-Learning contents. In conclusion, this study suggests that government should recommend and enact announce the use of cost estimation criteria(guidelines) of e-Learning content development and provide the institutional tools soon as possible.

Estimation of Solid Deposition in Sewer Systems using MOUSE Model (MOUSE 모형을 이용한 관거 내 고형물 퇴적량 산정)

  • Lee, Jae-Soo
    • Journal of Korea Water Resources Association
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    • 제40권5호
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    • pp.397-407
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    • 2007
  • The deposition of sewer solids during dry weather in combined sewer systems results in a loss of flow capacity that may restrict flow and cause a local flooding and enhanced solids deposition. In order to solve these problems and to manage sewer systems efficiently, development of estimation equations for solid sediments In sewer systems is needed. However, estimation of solid sediments has performed using specific methods such as computer model before the development of estimation equations. In this study, solid sediments in sewer systems were estimated using MOUSE model for Gunja drainage basin in Korea and the estimated results were verified using estimation equations developed by the U.S. Environmental Protection Agency. As results, the estimated values using MOUSE model are smaller than that of equations developed in 1977 but greater than that of equations developed in 1984. Although the comparison between simulated and measured solid deposition is difficult due to the absent of measurement data, the estimated values using MOUSE model is reliable and can be used to develop estimation equations for solid sediment in Gunja drainage basin.