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A review of tropical cyclone wind field models
Wills, J.A.B.,Lee, B.E.,Wyatt, T.A. Techno-Press 2000 Wind and Structures, An International Journal (WAS Vol.3 No.2
Engineered structures such as buildings and bridges in certain regions of the world need to be designed to withstand tropical cyclone winds, otherwise known as typhoons or hurricanes. In order to carry out this design, it is necessary to be able to estimate the maximum wind speeds likely to be encountered by the structure over its expected lifetime, say 100 years. Estimation of the maximum wind involves not only the overall strength of the tropical cyclone, but the variation of wind speed with radius from the centre, circumferential position, and with height above the ground surface. In addition, not only the mean wind speed, but also the gust factor must usually be estimated as well. This paper investigates a number of recent mathematical models of tropical cyclone structure and comments on their suitability for these purposes in a variety of scenarios.
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Myeongsu Kang,Jaeyoung Kim,Wills, Linda M.,Jong-Myon Kim Institute of Electrical and Electronics Engineers 2015 IEEE transactions on industrial electronics Vol. No.
<P>This paper presents a reliable fault diagnosis methodology for various single and multiple combined defects of low-speed rolling element bearings. This method temporally partitions an acoustic emission (AE) signal and selects a portion of the signal, which contains intrinsic information about the bearing failures. This paper then performs frequency analysis for the selected time-domain AE signal by using multilevel finite-impulse response filter banks to obtain the most informative subband signals involving abnormal symptoms of the bearing defects. It does this by using a 2-D visualization tool that represents the percentage of the Gaussian-mixture-model-based residual component-to-defect component ratios via time-varying and multiresolution envelope analysis (TVMREA). Then, fault signatures in the time and frequency domains are extracted in the informative subband signals. Since all the extracted fault features may not be equally useful for diagnosis, the proposed genetic algorithm (GA)-based discriminative feature analysis (GADFA) selects the most discriminative subset of fault signatures. In experiments, single and multiple combined bearing defects under various conditions are used to validate the effectiveness of this fault diagnosis scheme using TVMREA and GADFA. Experimental results indicate that this reliable fault diagnosis methodology accurately identifies bearing failure type across a variety of conditions. In addition, GADFA outperforms other state-of-the-art feature analysis techniques, yielding 7.3%-46.6% performance improvements in average classification accuracy.</P>
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Improvement Strategy for the Level of BIM Utilisation in the Australian Construction Industry
Ki Pyung Kim,Jayden Matheson,Joel Newton,Jarrad Wills KINFORMS 2021 Management Review Vol.16 No.2
Despite the various BIM guidelines and frameworks, the current BIM utilisation level in the Australian construction industry is low. To identify the current perceived BIM benefits among the design and construction professionals as well as investigate essential supports for BIM utilisation level improvement, the research conducted a questionnaire survey and several semi-constructed interviews among 45 design and construction professionals. The research identified that BIM is currently perceived as a useful tool enabling design and construction professionals to perform their tasks productively. While BIM is recognised as useful, there are concerns related to data security and access management and interoperability. Discipline-specific BIM guideline and standard and BIM Training are identified as crucial supports to improve BIM utilisation level in the design and construction industry. This research disclosed the importance of the BIM utilisation level improvement across the supply chain of a construction project. The findings will provide fundamental explanations of the way to improve BIM utilisation level in the Australian construction industry.
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Movement of trifluralin , metolachlor and metribuzin in the soil environment
Kim, Jung Ho,Feagley, S E,Southwick, L M,Wills, H W,Bengtson, R L 한국농화학회 1992 Applied Biological Chemistry (Appl Biol Chem) Vol.35 No.4
The objective of this study was to evaluate the runoff behavior and leaching properties in soil environment of trifluralin, metolachlor and metribuzin: herbicides used widely in Louisiana and other states with soybeans. Adsorption-desorption of the these herbicides trifluralin, metolachlor and metribuzin was studied in a selected soil (Clay loam). At a 1: 10 soil/water ratio, the Freundlich constant Kd, for trifluralin metolachlor and metribuzin were 9.97, 1.54 and 1.10 respectively. Leaching and distribution of these herbicides were evaluated in soil columns (id 5.4㎝×26㎝). When the soil columns were leached with three pore volume of water, the distribution of trifluralin in soil and Leachate water was 70.02% and 0.005% of the applied amount respectively. The distribution of metolachlor was 42.93% in soil and 21.33% in leachate water. The distribution of metribuzin was 8.88% in soil and 68.97% in leachate water. Metolachlor and metribuzin were readily leached while trifluralin was strongly adsorbed to the soil. The results of the study illustrate the strong correlation between adsorption-desorption properties and leaching properties. From Louisiana field plot applied 1683 g/㏊ trifluralin 2759 g/㏊ of metolachlor and 609 g/㏊ of metribuzin, half life the field was 0.083∼0.052 ng/㎖. The concentration of metolachlor and metribuzin were 19∼402 ng/㎖ and 1.5∼56.2 ng/㎖ respectively. The trifluralin loss in surface water from the field was 0.0016% (0.0269 g/㏊) of the amount applied on 3 times of run off events. The total in surface water was 12.34% (340.46 g/㏊) and 7.11% (43.29 g/㏊) respectively, for the metolachlor and metribuzin on 7 times of run off events. The concentration of trifluralin in 1 m and 2 m well were the range of 0.04 ng/㎖∼0.08 ng/㎖. This indicated that leaching of trifluralin was very low. The concentration of metolachlor in 1 m well was decreased froth 205.3 ㎎/㎖ during 17∼62 days after application. The concentration of metribuzin in 1 m well also was decreased from 64.2 ng/㎖ to 0.70 ng/㎖, but in 2 m well was increased from 1.9 ng/㎖ to 76.7 ng/㎖. A contamination of metolachlor and metribuzin in ground water were higher than trifluralin.
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Flicker Mitigation for a Grid-Connected Tidal and River Power Generator Using the BESS
S. Seo,J. Kim,E. Muljadi,S. Meor-Danial,M. Worthington,R. Wills 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
In the grid-connected tidal and river power generation, the water turbulence and the grid condition can induce the fluctuating output power. This power fluctuation may cause a power quality issue such as flicker, or voltage fluctuations, during the continuous operation. Hence, it is important to assess flicker emission and to mitigate flicker in order to solve this power quality issue. This paper proposes a Battery Energy Storage System (BESS) installed between the power converters of the tidal and river power system in order to mitigate flickers in different grid conditions. The BESS smooths the active power fluctuations and reduces flicker even from the weak grid with the low impedance angle in the distribution network. The feasibility of the proposed BESS system has been tested using a simplified simulation model with interconnected inverters developed in the validated simulation tool of PSCAD/EMTDC, and the obtained results from the case studies are presented.
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The Soviet Union's economic and political implosion ... the fate of North Korea?
Will Sung Yang 한국국방연구원 2008 The Korean Journal of Defense Analysis Vol.20 No.2
This paper examines the outlook for North Korea's economic and political future. It argues that North Korea will most probably meet its demise in the same way as did the former Soviet Union. That is, an economic implosion will occur causing the political collapse of North Korea. Contrary to popular belief that North Korea would sustain itself if it reformed its economic policies, this paper argues that, regardless of reform, North Korea will not be able to avoid the collapse of the state*and the Kim regime, for that matter. The only impact reform will have is with regard to time as it will merely delay the process of North Korea's collapse. The author wishes to stress that these assessments of North Korea's future will probably show a greater impact after Kim Jong Il has passed. It is unlikely that North Korea or the regime will collapse under Kim Jong Il's reign because his regime still has a strong authoritative grip over his state, which he controls by being the commander of the North Korean People's Army and various paramilitary apparatuses, and by control of the media. However, the decisions that Kim Jong Il makes now will be the indirect cause of various unintended consequences in the future. Once the economy of North Korea develops core values that are somewhat similar to the South's, it is highly likely that Seoul, with its economic leverage, will gain political leverage over Pyongyang. This will ultimately have its effects in reunifying the Korean peninsula under Seoul's terms after Kim Jong Il's passing. The author reiterates that both, the status quo or the reform option, will eventually lead to the North's collapse. The difference will be in regard to when.
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THE SDSS-IV EXTENDED BARYON OSCILLATION SPECTROSCOPIC SURVEY: OVERVIEW AND EARLY DATA
Dawson, Kyle S.,Kneib, Jean-Paul,Percival, Will J.,Alam, Shadab,Albareti, Franco D.,Anderson, Scott F.,Armengaud, Eric,Aubourg, É,ric,Bailey, Stephen,Bautista, Julian E.,Berlind, Andreas A.,Bers American Astronomical Society 2016 The Astronomical journal Vol.151 No.2
<P>In a six-year program started in 2014 July, the Extended Baryon Oscillation Spectroscopic Survey (eBOSS) will conduct novel cosmological observations using the BOSS spectrograph at Apache Point Observatory. These observations will be conducted simultaneously with the Time Domain Spectroscopic Survey (TDSS) designed for variability studies and the Spectroscopic Identification of eROSITA Sources (SPIDERS) program designed for studies of X-ray sources. In particular, eBOSS will measure with percent-level precision the distance-redshift relation with baryon acoustic oscillations (BAO) in the clustering of matter. eBOSS will use four different tracers of the underlying matter density field to vastly expand the volume covered by BOSS and map the large-scale-structures over the relatively unconstrained redshift range 0.6 < z < 2.2. Using more than 250,000 new, spectroscopically confirmed luminous red galaxies at a median redshift z = 0.72, we project that eBOSS will yield measurements of the angular diameter distance d(A)(z) to an accuracy of 1.2% and measurements of H(z) to 2.1% when combined with the z > 0.6 sample of BOSS galaxies. With similar to 195,000 new emission line galaxy redshifts, we expect BAO measurements of d(A)(z) to an accuracy of 3.1% and H(z) to 4.7% at an effective redshift of z = 0.87. A sample of more than 500,000 spectroscopically confirmed quasars will provide the first BAO distance measurements over the redshift range 0.9 < z < 2.2, with expected precision of 2.8% and 4.2% on d(A)(z) and H(z), respectively. Finally, with 60,000 new quasars and re-observation of 60,000 BOSS quasars, we will obtain new Lya forest measurements at redshifts z > 2.1; these new data will enhance the precision of d(A)(z) and H(z) at z > 2.1 by a factor of 1.44 relative to BOSS. Furthermore, eBOSS will provide improved tests of General Relativity on cosmological scales through redshift-space distortion measurements, improved tests for non-Gaussianity in the primordial density field, and new constraints on the summed mass of all neutrino species. Here, we provide an overview of the cosmological goals, spectroscopic target sample, demonstration of spectral quality from early data, and projected cosmological constraints from eBOSS.</P>
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