Quasi-residual quasi-symmetric designs

AbstractIt is shown that for each λ ⩾ 3, there are only finitely many quasi-residual quasi-symmetric (QRQS) designs and that for each pair of intersection numbers (x, y) not equal to (0, 1) or (1, 2), there are only finitely many QRQS designs.A design is shown to be affine if and only if it is QRQS with x = 0. A projective design is defined as a symmetric design which has an affine residual. For a projective design, the block-derived design and the dual of the point-derivate of the residual are multiples of symmetric designs

Suitable Strategies for In-plane Orbit Acquisition using Micro-thrusters

The deviations in the injection orbital parameters, resulting from launcher dispersions, need to be corrected through a set of acquisition maneuvers to achieve the desired nominal parameters. When multiple satellites are injected into a single orbital plane, as a part of constellation establishment, they have to positioned in the plane with appropriate semi-major axis ‘a’ and mean anomaly ‘M’. In this paper, three strategies are studied for achieving orbit acquisition. The first strategy is by deriving an analogy to the Linear Quadratic Regulator (LQR). The state dynamics and the control law are of the form X&= AX + BU and U = −KX . The feedback gain K is calculated by minimizing the cost function. Under this strategy the thrust (N) and velocity increment ( ÄV ) are functions of time and only the matrix K needs to be up-linked. Any revision in the current or the target states, will then lead to a simple re-calculation of K and up-linking them. The second strategy assumes that ÄV is same for each maneuver and calculates the number of maneuvers and the ÄV required for each maneuver. If the maneuvers are stopped for reasons like orbit assessment, and thruster performance evaluation, the strategy can be restarted easily without having any penalty on the overall ÄV. Besides these two strategies, a third strategy based on the application of Fuzzy Modified Potential Function is also studied for autonomous orbit acquisition with constraints in the path. By adding Fuzzy logic to the potential function it is shown that, maneuvers can be changed gradually ahead of the constraints. Onboard implementation related aspects are also briefly addressed for all the strategies

Merlion L & S Band System

Under the MERLION project name, Nanyang Technological University of Singapore has teamed up with Surrey Satellite Technology Ltd. of the UK and developed a sophisticated communication payload on the UoSAT-12 mini-satellite which was launched recently. The MERLION payload combines an analogue and digital regenerative transponder, with L-band uplink and S-band downlink. The transponder can be configured in-orbit for a variety of functions and experiments, and carries dual signal processors. The digital uplink comprises a frequency agile L-band receiver, and 9600bps FSK and IMbps BPSK demodulators. The frequency agile digital S-band downlink is intended for high speed data transfer and will be employed to perform a variety of communication experiments. It is also capable of low bit rate spread spectrum communications, together with convolutional coding options to investigate its performance in the highly dynamic environment of LEO. The downlink can be configured to perform link characterisation at these frequencies. In conjunction with the 80386EX based On-Board-Computers, the digital uplink and downlink system can be configured into a high rate Store-and-Forward transponder. This paper would introduce the basic Medion architecture and design considerations, to realise the above functionality within the scope of a low cost mission

<i>Neisseria</i> species as pathobionts in bronchiectasis

Neisseria species are frequently identified in the bronchiectasis microbiome, but they are regarded as respiratory commensals. Using a combination of human cohorts, next-generation sequencing, systems biology, and animal models, we show that bronchiectasis bacteriomes defined by the presence of Neisseria spp. associate with poor clinical outcomes, including exacerbations. Neisseria subflava cultivated from bronchiectasis patients promotes the loss of epithelial integrity and inflammation in primary epithelial cells. In vivo animal models of Neisseria subflava infection and metabolipidome analysis highlight immunoinflammatory functional gene clusters and provide evidence for pulmonary inflammation. The murine metabolipidomic data were validated with human Neisseria-dominant bronchiectasis samples and compared with disease in which Pseudomonas-, an established bronchiectasis pathogen, is dominant. Metagenomic surveillance of Neisseria across various respiratory disorders reveals broader importance, and the assessment of the home environment in bronchiectasis implies potential environmental sources of exposure. Thus, we identify Neisseria species as pathobionts in bronchiectasis, allowing for improved risk stratification in this high-risk group.Published versio

Waste plastic bottle cap polypropylene (PP) as coarse aggregate replacement in concrete

Polypropylene (PP) has been widely used by researchers to determine its performance in concrete matrix. Generally, PP will be crushed or reshaped into flakes, fibres or granular shapes. However, the cost and time consumption for processing will increased as the melting point of PP is around 170 oC. Hence, the novelty of this research was to determine the suitability of the polypropylene cap (without any alteration of shape) as coarse aggregate replacement in concrete. The results of slump test, rebound hammer test and compressive strength test shows that the PP cap were suitable to be replaced as coarse aggregate in concrete. The compressive strength of concrete with PP cap was 27.3 MPa, higher than 20 MPa which is suitable for general concrete work. Furthermore, the compressive strength results of concrete elevated to temperatures (100, 200, 300 and 600 oC) at the age of 28 days were also studied. From 100 oC to 300 oC, the results indicated that concrete with PP cap performed better than the control concrete. The coarse aggregate replaced by PP cap was fixed to 10 %. Based on the experimental results, It was concluded that the PP cap aggregates were suitable to replace as coarse aggregate in concret

香港主体性的失魂或回魂？：论《倩女幽魂》电影系列中的政治无意识 = Disappearance or reappearance of Hong Kong subjectivity’s soul? : a study of the political unconscious in “A Chinese Ghost Story” film series

香港电影1980至90年代的黄金时期已然逝去。随着2003年《内地与香港关于建立更紧密经贸关系的安排》（CEPA）的签订，中港合拍作为一种电影制片与营销模式更是大势所趋。然而，基于各种政治与市场因素，合拍片中的香港主体性难免逐步被磨蚀。但是，这并不完全意味着“香港电影已死”。本文以弗雷德里克•詹姆逊（Fredric Jameson）的政治无意识理论为思想核心，并结合一些文化研究学者如罗永生、洛枫、斯图亚特•霍尔（Stuart Hall）、王宏志、周蕾等人的学术观点，对港产片《倩女幽魂》三部曲和中港合拍片《新倩女幽魂》共四部电影文本进行政治化的解读。本文旨在揭示港产片《倩女幽魂》三部曲与香港当时政治生态的互动关系，以及电影在后来的合拍片中如何被重新包装，以不同的姿态继续为香港的文化与身份发声。The golden era of Hong Kong film of 1980- 90s is over. Followed by the signing of “Closer Economic Partnership Arrangement between Mainland and Hong Kong ” (CEPA), the close cooperation between Mainland and Hong Kong in the field of film production and marketing has become a conventional trend. However, due to the influence of political and marketing factors, the once prominent characteristic of Hong Kong’s subjectivity has been gradually effaced in co-production films. But, this does not mean that Hong Kong film is dead, as gathered from public opinion. The thesis basing the theory of “Political Unconsciousness” by Fredric Jameson as core argument, combining various academic views of respectable academics in the Cultural Studies field such as Law Wing Sang ,Natalia Chan ,Stuart Hall ,Lawrence Wang, and Rey Chow , politicized interpretation of “A Chinese Ghost Story ” film series .The thesis attempts to unveil the interaction between the Hong Kong-produced “A Chinese Ghost Story ”film series and its political ecology. Furthermore, it also discusses how the re-packaging of the co-produced film enabled “A Chinese Ghost Story” continues to represent issues of Hong Kong culture and identity in a different way.Bachelor of Art