Likelihood estimation for distributed parameter models for NASA Mini-MAST truss

A maximum likelihood estimation for distributed parameter models of large flexible structures was formulated. Distributed parameter models involve far fewer unknown parameters than independent modal characteristics or finite element models. The closed form solutions for the partial differential equations with corresponding boundary conditions were derived. The closed-form expressions of sensitivity functions led to highly efficient algorithms for analyzing ground or on-orbit test results. For an illustration of this approach, experimental data of the NASA Mini-MAST truss was used. The estimations of modal properties involve lateral bending modes and torsional modes. The results show that distributed parameter models are promising in the parameter estimation of large flexible structures

Modelling Exploratory Analysis Processes for eResearch

Financial markets produce high-frequency data and analysing it involves transforming the data, detecting patterns and testing financial models. These actions or steps form an exploratory analysis process (EAP). ADAGE is an open SOA incorporating a BPMS that allows users to model EAPs by composing analysis services. A typical application scenario is used to evaluate ADAGE’ s ability to express an EAP as a business process. It is shown that current BPMS technology cannot satisfactorily represent EAPs as fully executable business processes. Using the theory of situation awareness, EAPs are shown to be dynamic in nature. Hence three extensions based on the late composition technique are proposed: (1) a dynamic process representation of EAPs; (2) a process execution model; and (3) process templates to automate repetitive steps of EAPs

DATA MINING METHODOLOGY FOR DETERMINING THE OPTIMAL MODEL OF COST PREDICTION IN SHIP INTERIM PRODUCT ASSEMBLY

In order to accurately predict costs of the thousands of interim products that are assembled in shipyards, it is necessary to use skilled engineers to develop detailed Gantt charts for each interim product separately which takes many hours. It is helpful to develop a prediction tool to estimate the cost of interim products accurately and quickly without the need for skilled engineers. This will drive down shipyard costs and improve competitiveness. Data mining is used extensively for developing prediction models in other industries. Since ships consist of thousands of interim products, it is logical to develop a data mining methodology for a shipyard or any other manufacturing industry where interim products are produced. The methodology involves analysis of existing interim products and data collection. Pre-processing and principal component analysis is done to make the data “user-friendly” for later prediction processing and the development of both accurate and robust models. The support vector machine is demonstrated as the better model when there are a lower number of tuples. However as the number of tuples is increased to over 10000, then the artificial neural network model is recommended

Overcoming cancer therapy resistance by targeting inhibitors of apoptosis proteins and nuclear factor-kappa B

This is the published version, also available here: http://www.ajtr.org/810001A.html.Chemo- or radioresistance markedly impairs the efficacy of cancer therapy and involves anti-apoptotic signal transduction pathways that prevent cell death. In resistant cancer cells, both inhibitors of apoptosis proteins (IAPs) and nuclear factor-kappa B (NF-κB) play a pivotal role in preventing apoptosis triggered by a variety of stresses, facilitating them as potential targets in cancer treatment. Furthermore, mounting evidences have established the crosstalks between IAPs (eg. XIAP, cIAP-1, cIAP-2) and proteins involved in NF-κB signaling (eg. TRAF2, RIP1, TAB1). Second mitochondria-derived activator of caspases (Smac) is a mitochondrial protein that released into cytoplasm upon apoptotic stimuli. As Smac functions as an endogenous IAP inhibitor, small molecule Smac-mimetics are believed to neutralize IAPs function that results in liberating caspase activity and promoting apoptosis. Moreover, recent studies show that Smac-mimetics may kill cancer cells in a different manner, which involves inducing ubiquitination of cIAPs, regulating NF-κB signaling and facilitating TNFα- triggered, caspase-8-mediated apoptosis in a certain cancer cell types. In other cancer cells that are resistant to TNFα or chemo/radiotherapy, Smac-mimetic IAP-inhibitors can enhance ionizing radiation or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis, indicating the potential role of Smac- mimetics in overcoming acquired therapy-resistance. Such findings provide important impetus for utilizing IAP- inhibitors as novel adjuvant therapy for the TNFα–resistant, NF-κB constitutively active cancers that account for the majority of patients who are refractory to current therapeutic approaches. (AJTR810001)

Employment Opportunities for the Visually Impaired in Ghana

This survey study examined current employment status of visually impaired individuals in Ghana. It looked at some of the factors that militate against the successful employment and sustainability of individuals with visual impairment in the country. It reviewed some policies that relate to employment of persons with disability in general and how these policies translate to practical employment opportunities for the visually impaired in the country. Some members of four associations for and of the Blind in Ghana namely, the Ghana Society for the Blind, Ghana Association of the Blind, Ghana Blind Teachers Association, The Ghana Federation of the Disabled, 26 blind teachers in two Special Schools, 4 visually impaired retirees, 5 visually impaired beggars in Accra and 2 self-employed visually impaired were involved in the study. Both purposive and convenient sampling techniques were used in the selection of the sample size. A sixitem open-ended questionnaire in Braille and semi-structured interview guide were used to collect data and the analysis was done using both interpretive and verbatim expression methods. The findings of the study have revealed that access to job information is not an easy task for the visually impaired largely due to the absence of newspapers in Braille format. Even though, there are well articulated policies in Ghana towards the employment of persons with disabilities in general, these have not been effective. The labour market is competitive, unfriendly and characterized by negative public prejudice and disbelief. Keywords: Visually - Impaired; Employment Opportunity; Disabilities. International Journal of Educational Research Vol. 3 (2) 2007 pp. 275-28

Substrate Induced Structural and Dynamics Changes in Human Phosphomevalonate Iinase and Implications for Mechanism

Phosphomevalonate kinase (PMK) catalyzes an essential step in the mevalonate pathway, which is the only pathway for synthesis of isoprenoids and steroids in humans. PMK catalyzes transfer of the γ-phosphate of ATP to mevalonate 5-phosphate (M5P) to form mevalonate 5-diphosphate. Bringing these phosphate groups in proximity to react is especially challenging, given the high negative charge density on the four phosphate groups in the active site. As such, conformational and dynamics changes needed to form the Michaelis complex are of mechanistic interest. Herein, we report the characterization of substrate induced changes (Mg-ADP, M5P, and the ternary complex) in PMK using NMR-based dynamics and chemical shift perturbation measurements. Mg-ADP and M5P Kd\u27s were 6–60 μM in all complexes, consistent with there being little binding synergy. Binding of M5P causes the PMK structure to compress (τc = 13.5 nsec), whereas subsequent binding of Mg-ADP opens the structure up (τc = 15.6 nsec). The overall complex seems to stay very rigid on the psec-nsec timescale with an average NMR order parameter of S2 ∼0.88. Data are consistent with addition of M5P causing movement around a hinge region to permit domain closure, which would bring the M5P domain close to ATP to permit catalysis. Dynamics data identify potential hinge residues as H55 and R93, based on their low order parameters and their location in extended regions that connect the M5P and ATP domains in the PMK homology model. Likewise, D163 may be a hinge residue for the lid region that is homologous to the adenylate kinase lid, covering the “Walker-A” catalytic loop. Binding of ATP or ADP appears to cause similar conformational changes; however, these observations do not indicate an obvious role for γ-phosphate binding interactions. Indeed, the role of γ-phosphate interactions may be more subtle than suggested by ATP/ADP comparisons, because the conservative O to NH substitution in the β-γ bridge of ATP causes a dramatic decrease in affinity and induces few chemical shift perturbations. In terms of positioning of catalytic residues, binding of M5P induces a rigidification of Gly21 (adjacent to the catalytically important Lys22), although exchange broadening in the ternary complex suggests some motion on a slower timescale does still occur. Finally, the first nine residues of the N-terminus are highly disordered, suggesting that they may be part of a cleavable signal or regulatory peptide sequence. Proteins 2009. © 2008 Wiley-Liss, Inc

A piecewise continuous Timoshenko beam model for the dynamic analysis of tapered beam-like structures

Distributed parameter modeling offers a viable alternative to the finite element approach for modeling large flexible space structures. The introduction of the transfer matrix method into the continuum modeling process provides a very useful tool to facilitate the distributed parameter model applied to some more complex configurations. A uniform Timoshenko beam model for the estimation of the dynamic properties of beam-like structures has given comparable results. But many aeronautical and aerospace structures are comprised of non-uniform sections or sectional properties, such as aircraft wings and satellite antennas. This paper proposes a piecewise continuous Timoshenko beam model which is used for the dynamic analysis of tapered beam-like structures. A tapered beam is divided into several segments of uniform beam elements. Instead of arbitrarily assumed shape functions used in finite element analysis, the closed-form solution of the Timoshenko beam equation is used. Application of the transfer matrix method relates all the elements as a whole. By corresponding boundary conditions and compatible conditions a characteristic equation for the global tapered beam has been developed, from which natural frequencies can be derived. A computer simulation is shown in this paper, and compared with the results obtained from the finite element analysis. While piecewise continuous Timoshenko beam model decreases the number of elements significantly; comparable results to the finite element method are obtained

Applying transfer matrix method to the estimation of the modal characteristics of the NASA Mini-Mass Truss

It is beneficial to use a distributed parameter model for large space structures because the approach minimizes the number of model parameters. Holzer's transfer matrix method provides a useful means to simplify and standardize the procedure for solving the system of partial differential equations. Any large space structures can be broken down into sub-structures with simple elastic and dynamical properties. For each single element, such as beam, tether, or rigid body, we can derive the corresponding transfer matrix. Combining these elements' matrices enables the solution of the global system equations. The characteristics equation can then be formed by satisfying the appropriate boundary conditions. Then natural frequencies and mode shapes can be determined by searching the roots of the characteristic equation at frequencies within the range of interest. This paper applies this methodology, and the maximum likelihood estimation method, to refine the modal characteristics of the NASA Mini-Mast Truss by successively matching the theoretical response to the test data of the truss. The method is being applied to more complex configurations

Fundamental Limits of Multiple-Access Integrated Sensing and Communication Systems

A memoryless state-dependent multiple access channel is considered to model an integrated sensing and communication system, where two transmitters wish to convey messages to a receiver while simultaneously estimating the sensing state sequences through echo signals. In particular, the sensing states are assumed to be correlated with the channel state, and the receiver has imperfect channel state information. In this setup, improved inner and outer bounds for capacity-distortion region are derived. The inner bound is based on an achievable scheme that combines message cooperation and joint compression via distributed Wyner-Ziv coding at each transmitter, resulting in unified cooperative communication and sensing. The outer bound is based on the ideas of dependence balance for communication rate and rate-limited constraints on sensing distortion. The proposed inner and outer bounds are proved to improve the state-of-the-art bounds. Finally, numerical examples are provided to demonstrate that our new inner and outer bounds strictly improve the existing results