Angular Velocity Observer for Attitude Tracking on SO(3) with the Separation Property

Tse-Huai Wu,이태영 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.5

This paper studies a rigid body attitude tracking control problem with attitude measurements only, whenangular velocity measurements are not available. An angular velocity observer is constructed such that the estimatedangular velocity is guaranteed to converge to the true angular velocity asymptotically from almost all initialestimates. As it is developed directly on the special orthogonal group, which completely avoids singularities, complexities,or discontinuities caused by minimal attitude representations or quaternions. Then, the presented observeris integrated with a proportional-derivative attitude tracking controller to show a separation type property, whereexponential stability is guaranteed for the combined observer and attitude control system.

Hedging, Strategic Partnership, and Taiwan’s Relations with Japan Under the Ma Ying-jeou Administration

Tse-kang Leng,Nien-chung Chang Liao 인하대학교 국제관계연구소 2016 Pacific Focus Vol.31 No.3

This article examines Taiwan’s new hedging policy toward China and its evolving relations with Japan. Taiwan under President Ma Ying-jeou focused on hedging its bets against China’s rise through engagement, accommodation, and soft balancing. Meanwhile, Taipei and Tokyo are also forging a strategic partnership as they cautiously achieve low-commitment agreements for deeper cooperation, including signing an important fisheries agreement. Nevertheless, both international and domestic challenges may constrain the flexibility of Taipei’s hedging strategy. Given the uncertainty and complexity in East Asia, Taipei will continue its hedging strategy as a way to expand its external cooperation in the region.

Coping with China in Hard Times: Taiwan in Global and Domestic Aspects

Tse-Kang Leng 인하대학교 국제관계연구소 2011 Pacific Focus Vol.26 No.3

This paper argues that in the post-democratization era, the Taiwanese state devotes itself to create a comprehensive division of labor with China in favor of Taiwan. Both the DPP and KMT administrations have endeavored to re-intervene in fields like research and development to strengthen and upgrade industrial competitiveness. The Ma administration tries to adopt a policy of globalization with comprehensive engagements with China. However, political costs come with the efforts in deepening and institutionalizing such unique relationship. On the domestic front, the redistribution effect of the trade pact buttresses opposition forces to request a halt to further integration. To cope with the rise of China in hard times, the Taiwanese state chooses to adopt two-track policies to re-intervene into economic spheres of influence while searching for political compromise with China. From this aspect, the power of the Taiwanese state is not shrinking in the era of globalization. It requires more subtle ways to enhance capacities to co-exist with social forces in the domestic soil, and promote trust with major international players in the region. The state power is thus transformed and readjusted in a more complicated manner.

Numerical simulation of wind loading on roadside noise mitigation structures

TSE, K.T.,Yang, Yi,Shum, K.M.,Xie, Zhuangning Techno-Press 2013 Wind and Structures, An International Journal (WAS Vol.17 No.3

Numerical research on four typical configurations of noise mitigation structures and their characteristics of wind loads are reported in this paper. The turbulence model as well the model parameters, the modeling of the equilibrium atmospheric boundary layer, the mesh discretization etc., were carefully considered in the numerical model to improve the numerical accuracy. Also a numerical validation of one configuration with the wind tunnel test data was made. Through detailed analyses of the wind load characteristics with the inclined part and the wind incidence angle, it was found that the addition of an inclined part to a noise mitigation structure at-grade would affect the mean nett pressure coefficients on the vertical part, and that the extent of this effect depends on the length of the inclined part itself. The magnitudes of the mean nett pressure coefficients for both the vertical part and the inclined part of noise mitigation structure at-grade tended to increase with length of inclined part. Finally, a comparison with the wind load code British/European Standard BS EN 1991-1-4:2005 was made and the envelope of the mean nett pressure coefficients of the noise mitigation structures was given for design purposes. The current research should be helpful to improve current wind codes by providing more reasonable wind pressure coefficients for different configurations of noise mitigation structures.

Wind characteristics observed in the vicinity of tropical cyclones: An investigation of the gradient balance and super-gradient flow

Tse, K.T.,Li, S.W.,Lin, C.Q.,Chan, P.W. Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.19 No.3

Through comparing the mean wind profiles observed overland during the passages of four typhoons, and the gradient wind speeds calculated based on the sea level pressure data provided by a numerical model, the present paper discusses, (a) whether the gradient balance is a valid assumption to estimate the wind speed in the height range of 1250 m ~ 1750 m, which is defined as the upper-level mean wind speed, in a tropical cyclone over land, and (b) if the super-gradient feature is systematically observed below the height of 1500 m in the tropical cyclone wind field over land. It has been found that, (i) the gradient balance is a valid assumption to estimate the mean upper-level wind speed in tropical cyclones in the radial range from the radius to the maximum wind (RMW) to three times the RMW, (ii) the super-gradient flow dominates the wind field in the tropical cyclone boundary layer inside the RMW and is frequently observed in the radial range from the RMW to twice the RMW, (iii) the gradient wind speed calculated based on the post-landfall sea level pressure data underestimates the overall wind strength at an island site inside the RMW, and (iv) the unsynchronized decay of the pressure and wind fields in the tropical cyclone might be the reason for the underestimation.

Wind pressure characteristics for a double tower high-rise structure in a group of buildings

Tse, K.T.,Wang, D.Y.,Zhou, Y. Techno-Press 2013 Wind and Structures, An International Journal (WAS Vol.16 No.5

Wind pressure characteristics on a double tower high-rise structure, which is disturbed by surrounding buildings, were investigated using large eddy simulation (LES) and 1:300 scale wind tunnel experiments. The computational simulation technique and wind tunnel experimental technique were described in detail initially. Comparisons of computational results with the experimental data have subsequently been carried out to validate the reliability of LES. Comparisons have been performed in detail for the mean and fluctuating pressure coefficients. Detailed explanations of each comparison were given in the paper. To study further on the pressure coefficients on the building surfaces, parametric studies on shape coefficient and spatial correlation were performed and investigated. The numerical and experimental results presented in this paper advance understanding on wind field around buildings and the application of LES and wind tunnel tests.

Evaluation of mode-shape linearization for HFBB analysis of real tall buildings

Tse, K.T.,Yu, X.J.,Hitchcock, P.A. Techno-Press 2014 Wind and Structures, An International Journal (WAS Vol.18 No.4

The high frequency base balance (HFBB) technique is a convenient and relatively fast wind tunnel testing technique for predicting wind-induced forces for tall building design. While modern tall building design has seen a number architecturally remarkable buildings constructed recently, the characteristics of those buildings are significantly different to those that were common when the HFBB technique was originally developed. In particular, the prediction of generalized forces for buildings with 3-dimensional mode shapes has a number of inherent uncertainties and challenges that need to be overcome to accurately predict building loads and responses. As an alternative to the more conventional application of general mode shape correction factors, an analysis methodology, referred to as the linear-mode-shape (LMS) method, has been recently developed to allow better estimates of the generalized forces by establishing a new set of centers at which the translational mode shapes are linear. The LMS method was initially evaluated and compared with the methods using mode shape correction factors for a rectangular building, which was wind tunnel tested in isolation in an open terrain for five incident wind angles at $22.5^{\circ}$ increments from $0^{\circ}$ to $90^{\circ}$. The results demonstrated that the LMS method provides more accurate predictions of the wind-induced loads and building responses than the application of mode shape correction factors. The LMS method was subsequently applied to a tall building project in Hong Kong. The building considered in the current study is located in a heavily developed business district and surrounded by tall buildings and mixed terrain. The HFBB results validated the versatility of the LMS method for the structural design of an actual tall building subjected to the varied wind characteristics caused by the surroundings. In comparison, the application of mode shape correction factors in the HFBB analysis did not directly take into account the influence of the site specific characteristics on the actual wind loads, hence their estimates of the building responses have a higher variability.

Congenital Heart Disease: a Pictorial Illustration of Putting Segmental Approach into Practice

Tse Hang Yeung,박은아,Ying Cheong Lee,유진영,Choi Yu Lui 대한자기공명의과학회 2015 Investigative Magnetic Resonance Imaging Vol.19 No.4

The human heart is a complex organ in which many complicated congenital defectsmay happen and some of them require surgical intervention. Due to the vastcomplexity of varied anatomical presentations, establishing an accurate and consistentnomenclature system is utmost important to facilitate effective communication amongpediatric cardiologists, cardiothoracic surgeons and radiologists. The Van Praaghsegmental approach to the complex congenital heart disease (CHD) was developed inthe 1960s and has been used widely as the language for describing complex anatomyof CHD over the decades. It utilizes a systematic and sequential method to describe thecardiac segments and connections which in turn allows accurate, comprehensive andunambiguous description of CHD. It can also be applied to multiple imaging modalitiessuch as echocardiogram, cardiac CT and MRI. The Van Praagh notation demonstrates agroup of three letters, with each letter representative for a key embryologic region ofcardiac anatomy: the atria, ventricles and great vessels. By using a 3-steps approach,we can evaluate complex CHD precisely and have no difficulties in communicatingwith other medial colleague. This pictorial essay revisits the logical steps of segmentalapproach, followed by a pictorial illustration of its application.

Literacy Education in Multi-lingual and Multi-cultural Societies : The Hong Kong Experience

Tse Shek Kam 서울대학교 국어교육연구소 2015 국어교육연구 Vol.36 No.-

Since its reunification with China in 1997, the former British colony of Hong Kong has changed from being a bi-lingual (Cantonese and English) to a tri-lingual state (Cantonese, English and Mandarin/Putonghua, the language spoken across Mainland China). Since gaining independence, Hong Kong has witnessed a steady influx of non-Chinese-speaking immigrants whose children present a worrying problem for their Chinese-speaking teachers since all pupils are expected to learn, converse and write in Chinese in school. This paper presents a framework for teaching Chinese to non-Chinese speaking pupils in Hong Kong, a framework assembled from the experiences of teachers who teach non-Chinese-speaking pupils; from the recommendations in the curriculum prescribed by the Hong Kong Educational Bureau; and from scholarly publications on the matter from experts in the field. The actions taken and strategies used as teachers and schools attempt to tackle the problem are discussed, particularly the use of differentiated curricula, the use of diverse teaching materials and resources, and experimentation with teaching strategies so that all pupils may learn.

Heat and Mass Transfer in Vitrification of Bio-and-Food Materials

Tse Chao Hua,Bao Lin Liu 대한기계학회 1998 Heat transter conference Vol.1 No.1