Integrating engineering design and analysis using a multi-representation approach

With the present gap between CAD and CAE, designers are often hindere in their efforts to explore design alternatives and ensure product robustness. This paper describes the multi-representation architecture (MRA)—a design-analysis integration strategy that views CAD-CAE integration as an information-intensive mapping between design models and analysis models. The MRA divides this mapping into subproblems using four information representations: solution method models (SMMs), analysis building blocks (ABBs), product models (PMs), and product model-based analysis models (PBAMs). A key distinction is the explicit representation of design-analysis associativity as PM-ABB idealization linkages that are contained in PBAMs.The MRA achieves flexibility by supporting different solution tools and design tools, and by accommodating analysis models of diverse discipline, complexity and solution method. Object and constraint graph techniques provide modularity and rich semantics.Priority has been given to the class of problems termedroutine analysis—the regular use of established analysis models in product design. Representative solder joint fatigue case studies demonstrate that the MRA enables highly automated routine analysis for mixed formula-based and finite element-based models. Accordingly, one can employ the MRA and associated methodology to create specialized CAE tools that utilize both design information and general purpose solution tools.Nomenclature MRA multi-representation architecture - SMM solution method model - ABB analysis building block - PM product model - PBAM product model-based analysis model - ABB-SMM transformation - idealization relation between design and analysis attributes - PM-ABB associativity linkage indicating usage of one or more _i eislab. eislab. gatech. edu.     

Quantification of coumarin derivatives in Noni (Morinda citrifolia) and their contribution of quenching effect on reactive oxygen species

The quantification of coumarin derivatives such as scopoletin, 7-hydroxycoumarin (7-HC) and 4-hydroxycoumarin (4-HC) in Noni (Morinda citrifolia) was described. The coumarin derivatives were determined by HPLC-UV or -fluorescence detection. More than 95% of peak purity for coumarin derivatives in Noni sample was confirmed by a multi-wavelength fluorescence detector. Amounts of scopoletin and 7-HC in Noni juices (A–H) were ranging 5.1–231 μg/ml and 0.04–0.45 μg/ml, respectively (n = 12). No 4-HC was detected in any Noni samples examined.     

Geotechnical Aspects of Groundwater Control

Due to the increasing world population growth and competition for space, especially in bigger cities, the construction of subsurface civil engineering structures has become unavoidable. Safety, both during and after the construction of such structures, is of paramount importance to civil engineers. One of the main challenges in securing this safety is presented in the form of groundwater flow and its control. In this paper, the state of the art techniques for controlling groundwater flow during underground excavation are outlined with case studies from some construction sites in Japan. It needs to be pointed out that no single technique is adequate for controlling groundwater flow at an excavation site. Also, not so much attention has been paid to the designed groundwater level, which plays a major role in the stability of the structure after construction. In addition, groundwater conservation has yet to be considered in the designs of such structures. It is necessary for by-passes for groundwater flow to be constructed and monitored over the long term to assess their performances.     

Signature schemes with a fuzzy private key

In this paper, we introduce a new concept of digital signature that we call fuzzy signature, which is a signature scheme that uses a noisy string such as biometric data as a private key, but does not require user-specific auxiliary data (which is also called a helper string in the context of fuzzy extractors), for generating a signature. Our technical contributions are threefold: (1) we first give the formal definition of fuzzy signature, together with a formal definition of a “setting” that specifies some necessary information for fuzzy data. (2) We give a generic construction of a fuzzy signature scheme based on a signature scheme that has certain homomorphic properties regarding keys and satisfies a kind of related key attack security with respect to addition, and a new tool that we call linear sketch. (3) We specify two concrete settings for fuzzy data, and for each of the settings give a concrete instantiation of these building blocks for our generic construction, leading to two concrete fuzzy signature schemes. We also discuss how fuzzy signature schemes can be used to realize a biometric-based PKI that uses biometric data itself as a cryptographic key, which we call the public biometric infrastructure.

     

Motion control and shape optimization of a suitlike flexible arm

A method of motion control as well as shape optimization is proposed for the preliminary design of a suitlike flexible arm, which is composed of some variable-length and fixed-length beams. The large deformation, variable geometry and motion of the flexible structure are calculated by dynamic finite element analysis (FEA) using the step by step time integration method. A neural-networks-inverse-model, which learns nonlinear behaviour of the flexible structure, has been applied for the motion control as an inverse model of the flexible arm. For this geometrically nonlinear structure and time response problem, the optimum shape of the cross-section has been calculated under constraints of stress, stiffness and minimum weight with FEA and sensitivity analysis combined with fuzzy rules. This method has been applied for the design of a flexible arm, which simulates a process of lifting a human body and moving it. The calculated optimum shape has a much higher stiffness with decrease in weight in comparison with the initial shape. Moreover, the calculated motion agrees well with the one aimed for and the flexible arm reduces the impact force.     

Ursodeoxycholic acid corrects defective natural killer activity by inhibiting prostaglandin E2 production in primary biliary cirrhosis

We evaluated the effect of ursodeoxycholic acid on the defective natural killer activity in primary biliary cirrhosis. Administration of ursodeoxycholic acid (600 mg daily) for one month significantly increased natural killer activity in patients with primary biliary cirrhosis (P < 0.05). Ursodeoxycholic acid also enhanced the in vitro natural killer activity of lymphocytes from healthy volunteers, while other hydrophobic bile acids depressed it. Furthermore, ursodeoxycholic acid reduced the prostaglandin E2 concentration in culture supernatants of lymphocytes from healthy volunteers to a lower level than that in culture incubated with chenodeoxycholic acid (P < 0.05) or control cultures (P < 0.01). Urosdeoxycholic acid normalized the defective natural killer activity in primary biliary cirrhosis by reducing the levels of other hydrophobic bile acids and inhibiting prostaglandin E2 production, suggesting that it may be a useful immunomodulating agent for primary biliary cirrhosis.     

Nitrogen availability to maize as affected by fertilizer application and soil type in the Tanzanian highlands

Enhancing crop production by maintaining a proper synchrony between soil nitrogen (N) and crop N demand remains a challenge, especially in under-studied tropical soils of Sub-Saharan Africa (SSA). For two consecutive cropping seasons (2013–2015), we monitored the fluctuation of soil inorganic N and its availability to maize in the Tanzanian highlands. Different urea-N rates (0–150 kg N ha^?1; split into two dressings) were applied to two soil types (TZi, sandy Alfisols; and TZm, clayey Andisols). In the early growing season, soil mineralized N was exposed to the leaching risk due to small crop N demand. In the second N application (major N supply accounting for two-thirds of the total N), applied urea was more efficient in increasing soil inorganic N availability at TZm than at TZi. Such effect of soil type could be the main contributor to the higher yield at TZm (up to 4.4 Mg ha^?1) than that at TZi (up to 2.6 Mg ha^?1) under the same N rate. The best-fitted linear-plateau model indicated that the soil inorganic N availability (0–0.3 m) at the tasseling stage largely accounted for the final yield. Further, yields at TZi were still limited by N availability at the tasseling stage due to fast depletion of applied-N, whereas yields plateaued at TZm once N availability was above 67 kg N ha^?1. Our results provided a valuable reference for designing the N management to increase yield, while minimizing the potentially adverse losses of N to the environment, in different agro-ecological zones in SSA.