Extracting Time-Varying Mean Component of Non-Stationary Winds Utilizing Vondrak Filter and Genetic Algorithm: A Wind Engineering Perspective

2021 ◽  
pp. 2150155
Author(s):  
Kang Cai ◽  
Xiao Li ◽  
Lun Hai Zhi
Keyword(s):  
Genetic Algorithm ◽  
Vital Role ◽  
Wind Engineering ◽  
Time Varying ◽  
Gust Factor ◽  
Wind Characteristics ◽  
Vondrak Filter ◽  
Wind Induced Vibration ◽  
Wind Induced Vibration Response

The time-varying mean (TVM) component plays a vital role in the characterization of non-stationary winds, whereas it is difficult to extract the TVM accurately or to validate it quantitively. To deal with this problem, this paper first develops two additional conditions for the TVM extraction from the perspective of structural wind-induced vibration response, then presents an approach, based on the combination of Vondrak filter and genetic algorithm (Vondrak-G), to derive the optimal TVM from non-stationary wind speed records as well as its turbulence characteristics (i.e. gust factor, turbulence intensity, and turbulence integral length scale). Furthermore, the wind characteristics obtained by the Vondrak-G approach are compared with those by a conventional approach derived for stationary winds, demonstrating that the results by the Vondrak-G approach are evidently more accurate. This paper aims to provide an effective method for accurately extracting the TVM and then evaluating wind characteristics of the non-stationary wind.

Wind-Induced Vibration Response Analysis of a High-Rise Structure

2011 ◽  
Vol 94-96 ◽  
pp. 999-1002
Author(s):  
Yu Jie Pan ◽  
Zhong Rong Lv ◽  
Ji Ke Liu
Keyword(s):  
Random Process ◽  
Wind Engineering ◽  
Computational Time ◽  
Induced Response ◽  
Response Analysis ◽  
High Rise ◽  
Engineering Vibration ◽  
New Tv ◽  
Wind Induced Vibration ◽  
Wind Induced Vibration Response

Autoregressive (AR) method can provide a simulation of random process with relatively short computational time and acceptable accuracy while Newmark-β Method is a quick way to accomplish the response analysis. Therefore in this paper, the combination of these two methods will solve the problem of wind-induced response analysis quickly and precisely. According to several theories, such as wind engineering, vibration theory and random process, we succeed to model 37-dimensional correlated random wind velocity and it is used for the response analysis. Then we utilize Newmark-β method to analyze successfully and the key results demonstrate that Guangzhou New TV Tower does not satisfy the requirements in the building code of China thus vibration control is needed.

scholarly journals A Field Measurement Based Wind Characteristics Analysis of a Typhoon in Near-Ground Boundary Layer

Atmosphere ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 873
Author(s):  
Dandan Xia ◽  
Liming Dai ◽  
Li Lin ◽  
Huaifeng Wang ◽  
Haitao Hu
Keyword(s):  
Turbulence Intensity ◽  
Field Measurement ◽  
Three Dimensional ◽  
Wind Data ◽  
Statistical Characteristics ◽  
Gust Factor ◽  
Characteristics Analysis ◽  
Wind Characteristics ◽  
The Mean ◽  
The Relationship

The field measurement was conducted to observe the wind field data of West Pacific typhoon “Maria” in this research. With the application of ultrasonic anemometers installed in different heights (10 m, 80 m, 100 m) of the tower, the three dimensional wind speed data of typhoon “Maria” was acquired. In addition, vane-type anemometers were installed to validate the accuracy of the wind data from ultrasonic anemometers. Wind characteristics such as the mean wind profile, turbulence intensity, integral length scale, and wind spectrum are studied in detail using the collected wind data. The relationship between the gust factor and turbulence intensity was also studied and compared with the existing literature to demonstrate the characteristics of Maria. The statistical characteristics of the turbulence intensity and gust factor are presented. The corresponding conclusion remarks are expected to provide a useful reference for designing wind-resistant buildings and structures.

scholarly journals U.S. TREND INFLATION REINTERPRETED: THE ROLE OF FISCAL POLICIES AND TIME-VARYING NOMINAL RIGIDITIES

2014 ◽  
Vol 19 (6) ◽  
pp. 1294-1308 ◽  
Author(s):  
Nicola Acocella ◽  
Giovanni Di Bartolomeo ◽  
Patrizio Tirelli
Keyword(s):  
Strong Impact ◽  
Fiscal Policies ◽  
Time Varying ◽  
Nominal Rigidities ◽  
Distortionary Taxation ◽  
Trend Inflation ◽  
Wage Indexation ◽  
Joint Evolution

This paper offers a reinterpretation of the Fed's time-varying implicit inflation target, based on two considerations. The first is that the need to alleviate the burden of distortionary taxation may justify the choice of a positive inflation rate. The second is based on compelling evidence that the degree of price and wage indexation falls with trend inflation. In fact, we find that a proper characterization of the joint evolution of fiscal variables and nominal rigidities has a strong impact on the Ramsey optimal policies, implying optimal inflation dynamics that are consistent with the observed evolution of U.S. trend inflation. By contrast, tax policies have been too lax, especially at the time of the controversial Bush tax cuts.

Discussion of “Characterization of Time-Varying Organic Loads”

1972 ◽  
Vol 98 (2) ◽  
pp. 444-455
Author(s):  
Francis Clay McMichael ◽  
Frank C. Vigani
Keyword(s):  
Time Varying

Measurement Scheme Synthesis in Multi-Station Machining Systems

Manufacturing ◽  
2002 ◽  
Author(s):  
Dragan Djurdjanovic ◽  
Jun Ni
Keyword(s):  
Genetic Algorithm ◽  
Formal Methods ◽  
Cylinder Head ◽  
Human Intervention ◽  
Quantitative Characterization ◽  
Measurement Scheme ◽  
Engine Cylinder ◽  
Synthesis Procedure ◽  
Selection Of

The selection of measurements in multi-station machining systems is currently not a systematic process and it involves expert human intervention. In this paper, the recently introduced formal methods for quantitative characterization of measurement schemes in multi-station machining systems are employed in devising systematic measurement scheme synthesis procedures. The newly proposed synthesis procedures were applied in devising measurement schemes in the process used to machine a car engine cylinder head. It was observed that the measurement scheme synthesis procedure based on a genetic algorithm robustly outperformed the synthesis procedures based on the heuristics of successive measurement removal.

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