• 제목/요약/키워드: property prediction

검색결과 508건 처리시간 0.022초

PSC 박스거더 교량에 사용된 세그먼트 콘크리트의 크리프 및 건조수축에 관한 실험적 연구 (An Experimental Study on the Creep and Shrinkage for the Segment Concrete in PSC Box Girder Bridge)

  • 최한태;윤영수;이만섭
    • 콘크리트학회논문집
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    • 제11권3호
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    • pp.23-34
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    • 1999
  • In designing PSC box girder bridge, the dead load, prestressing force, creep and shrinkage of concrete are the main factors which influence the camber and deflection of segmental concrete structure under construction. Among these factors the creep and shrinkage are the functions of the time-dependent property which, therefore, must considered with time. The prediction model for estimating creep and shrinkage of concrete has been suggested by ACI, CEB/FIP, JSCE and KSCE design code. In this study the creep and shrinkage test were carried out for four curing ages of concrete which was applied to the pretressed concrete box-girder bridge at a construction site, and the results of test were compared to the values of prediction by the design code. Shrinkage test shows that the test results are similar to KSCE-96 and JSCE-96 but very higher than other prediction model and creep test results are generally similar to ACI-209 and DSCE-96 but lower than other prediction models in contrast to shrinkage test.

유한요소해석을 이용한 탄소강의 담금질 공정에 대한 상변태 및 기계적 성질 예측 (Prediction of Phase Transformation and Mechanical Property of Carbon Steel in Quenching based on Finite Element Analysis)

  • 김동규;정경환;강성훈;임용택
    • 한국소성가공학회:학술대회논문집
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    • 한국소성가공학회 2009년도 추계학술대회 논문집
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    • pp.173-176
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    • 2009
  • A great emphasis has been placed on the design of heat treatment process to achieve desired microstructure and mechanical property of final product. In this study, finite element analysis was carried out to predict temperature, microstructure and hardness of eutectoid steel after water quenching. Convective heat transfer coefficients were determined by inverse analysis using surface temperatures measured with three different installation methods of thermocouples. Finally, the effect of convective heat transfer coefficients on the prediction of temperature history and hardness was analyzed by comparing experimental and simulation results.

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수분함량예측기법을 이용한 토양 열특성 예측에 관한 연구 (A Study on the Prediction of the Soil Thermal Property Using Predicting the Soil Moisture Contents)

  • 정성환;김대경;최상봉;배정효;하태현;이현구;조성배;강지원;곽방명;윤형희
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2000년도 하계학술대회 논문집 A
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    • pp.576-578
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    • 2000
  • This paper address the prediction method of a soil thermal property depending on soil moisture contents and suggests the guideline to determine the soil thermal resistivity for the calculation of the cuurent carrying capacity of underground power cables in Korea.

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Moderately clipped LASSO for the high-dimensional generalized linear model

  • Lee, Sangin;Ku, Boncho;Kown, Sunghoon
    • Communications for Statistical Applications and Methods
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    • 제27권4호
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    • pp.445-458
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    • 2020
  • The least absolute shrinkage and selection operator (LASSO) is a popular method for a high-dimensional regression model. LASSO has high prediction accuracy; however, it also selects many irrelevant variables. In this paper, we consider the moderately clipped LASSO (MCL) for the high-dimensional generalized linear model which is a hybrid method of the LASSO and minimax concave penalty (MCP). The MCL preserves advantages of the LASSO and MCP since it shows high prediction accuracy and successfully selects relevant variables. We prove that the MCL achieves the oracle property under some regularity conditions, even when the number of parameters is larger than the sample size. An efficient algorithm is also provided. Various numerical studies confirm that the MCL can be a better alternative to other competitors.

Meso-Scale Approach for Prediction of Mechanical Property and Degradation of Concrete

  • Ueda, Tamon
    • Corrosion Science and Technology
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    • 제3권3호
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    • pp.87-97
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    • 2004
  • This paper presents a new approach with meso scale structure models to express mechanical property, such as stress - strain relationships, of concrete. This approach is successful to represent both uniaxial tension and uniaxial compression stress - strain relationship, which is in macro scale. The meso scale approach is also applied to predict degraded mechanical properties of frost-damaged concrete. The degradation of mechanical properties with frost-damaged concrete was carefully observed. Strength and stiffness in both tension and compression decrease with freezing and thawing cycles (FTC), while stress-free crack opening in tension softening increases. First attempt shows that the numerical simulation can express the experimentally observed degradation by introducing changes in the meso scale structure in concrete, which are assumed based on observed damages in the concrete subjected to FTC. At the end applicability of the meso scale approach to prediction of the degradation by combined effects of salt attack and FTC is discussed. It is shown that clarification of effects of frost damage in concrete on corrosion progress and on crack development in the damaged cover concrete due to corrosion is one of the issues for which the meso scale approach is useful.

Prediction of dynamic soil properties coupled with machine learning algorithms

  • Dae-Hong Min;Hyung-Koo Yoon
    • Geomechanics and Engineering
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    • 제37권3호
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    • pp.253-262
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    • 2024
  • Dynamic properties are pivotal in soil analysis, yet their experimental determination is hampered by complex methodologies and the need for costly equipment. This study aims to predict dynamic soil properties using static properties that are relatively easier to obtain, employing machine learning techniques. The static properties considered include soil cohesion, friction angle, water content, specific gravity, and compressional strength. In contrast, the dynamic properties of interest are the velocities of compressional and shear waves. Data for this study are sourced from 26 boreholes, as detailed in a geotechnical investigation report database, comprising a total of 130 data points. An importance analysis, grounded in the random forest algorithm, is conducted to evaluate the significance of each dynamic property. This analysis informs the prediction of dynamic properties, prioritizing those static properties identified as most influential. The efficacy of these predictions is quantified using the coefficient of determination, which indicated exceptionally high reliability, with values reaching 0.99 in both training and testing phases when all input properties are considered. The conventional method is used for predicting dynamic properties through Standard Penetration Test (SPT) and compared the outcomes with this technique. The error ratio has decreased by approximately 0.95, thereby validating its reliability. This research marks a significant advancement in the indirect estimation of the relationship between static and dynamic soil properties through the application of machine learning techniques.

보다 정확한 동적 상황인식 추천을 위해 정확 및 오류 패턴을 활용하여 순차적 매칭 성능이 개선된 상황 예측 방법 (Context Prediction Using Right and Wrong Patterns to Improve Sequential Matching Performance for More Accurate Dynamic Context-Aware Recommendation)

  • 권오병
    • Asia pacific journal of information systems
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    • 제19권3호
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    • pp.51-67
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    • 2009
  • Developing an agile recommender system for nomadic users has been regarded as a promising application in mobile and ubiquitous settings. To increase the quality of personalized recommendation in terms of accuracy and elapsed time, estimating future context of the user in a correct way is highly crucial. Traditionally, time series analysis and Makovian process have been adopted for such forecasting. However, these methods are not adequate in predicting context data, only because most of context data are represented as nominal scale. To resolve these limitations, the alignment-prediction algorithm has been suggested for context prediction, especially for future context from the low-level context. Recently, an ontological approach has been proposed for guided context prediction without context history. However, due to variety of context information, acquiring sufficient context prediction knowledge a priori is not easy in most of service domains. Hence, the purpose of this paper is to propose a novel context prediction methodology, which does not require a priori knowledge, and to increase accuracy and decrease elapsed time for service response. To do so, we have newly developed pattern-based context prediction approach. First of ail, a set of individual rules is derived from each context attribute using context history. Then a pattern consisted of results from reasoning individual rules, is developed for pattern learning. If at least one context property matches, say R, then regard the pattern as right. If the pattern is new, add right pattern, set the value of mismatched properties = 0, freq = 1 and w(R, 1). Otherwise, increase the frequency of the matched right pattern by 1 and then set w(R,freq). After finishing training, if the frequency is greater than a threshold value, then save the right pattern in knowledge base. On the other hand, if at least one context property matches, say W, then regard the pattern as wrong. If the pattern is new, modify the result into wrong answer, add right pattern, and set frequency to 1 and w(W, 1). Or, increase the matched wrong pattern's frequency by 1 and then set w(W, freq). After finishing training, if the frequency value is greater than a threshold level, then save the wrong pattern on the knowledge basis. Then, context prediction is performed with combinatorial rules as follows: first, identify current context. Second, find matched patterns from right patterns. If there is no pattern matched, then find a matching pattern from wrong patterns. If a matching pattern is not found, then choose one context property whose predictability is higher than that of any other properties. To show the feasibility of the methodology proposed in this paper, we collected actual context history from the travelers who had visited the largest amusement park in Korea. As a result, 400 context records were collected in 2009. Then we randomly selected 70% of the records as training data. The rest were selected as testing data. To examine the performance of the methodology, prediction accuracy and elapsed time were chosen as measures. We compared the performance with case-based reasoning and voting methods. Through a simulation test, we conclude that our methodology is clearly better than CBR and voting methods in terms of accuracy and elapsed time. This shows that the methodology is relatively valid and scalable. As a second round of the experiment, we compared a full model to a partial model. A full model indicates that right and wrong patterns are used for reasoning the future context. On the other hand, a partial model means that the reasoning is performed only with right patterns, which is generally adopted in the legacy alignment-prediction method. It turned out that a full model is better than a partial model in terms of the accuracy while partial model is better when considering elapsed time. As a last experiment, we took into our consideration potential privacy problems that might arise among the users. To mediate such concern, we excluded such context properties as date of tour and user profiles such as gender and age. The outcome shows that preserving privacy is endurable. Contributions of this paper are as follows: First, academically, we have improved sequential matching methods to predict accuracy and service time by considering individual rules of each context property and learning from wrong patterns. Second, the proposed method is found to be quite effective for privacy preserving applications, which are frequently required by B2C context-aware services; the privacy preserving system applying the proposed method successfully can also decrease elapsed time. Hence, the method is very practical in establishing privacy preserving context-aware services. Our future research issues taking into account some limitations in this paper can be summarized as follows. First, user acceptance or usability will be tested with actual users in order to prove the value of the prototype system. Second, we will apply the proposed method to more general application domains as this paper focused on tourism in amusement park.

CPB(Cold-Pad-Batch) 염색 패더롤 고무에서 화학적 노화로 인한 가속 수명예측 (Accelerated Life Prediction of CPB(cold-pad-batch) Padder Roll Rubber to Chemical Degradation)

  • 임지영;남창우;이우성
    • 한국염색가공학회지
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    • 제29권3호
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    • pp.155-161
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    • 2017
  • In CPB(Cold-Pad-Batch) dyeing, the rubber of the padder roll is influenced by the heat, chemical and mechanical influences and thus aging of the padder roll rubber occurs. This study presents an accelerated thermal aging test of the CPB padder roll rubber with strong alkali conditions. Using Arrhenius formula of the various property values for the various aging temperatures($80^{\circ}C$, $90^{\circ}C$, $100^{\circ}C$) of the padder roll, the accelerated life predictions could be calculated. The threshold value of the property was set at different values. The hardness was set at the point where 5% degradation occurs based on the actual use conditions, and the tensile strength was set at the point where 50% degradation occurs based on the general life prediction standards. From the results of the different physical properties at differing temperatures, the Arrhenius plot could be obtained. Through the usage of the Arrhenius Equation, significant duration expectation could be predicted, and the chemical aging behavior of the CPB padder roll could be found at the arbitrary and actual temperatures.