Reasoning by Analogy in a Multi-Level System Architecture for the Design of Mechanisms

Since the first attempts to integrate AI technology and engineering design nearly two decades ago, few expert systems have been shown to demonstrate sufficient reasoning capabilities to solve real-world design problems. The complex nature of design, the lack of understanding of the design process, and the limitations of current expert system technology have all been shown to have adverse effects on the maturity of this research area. Therefore, our direction in this research concentrates on understanding the design process, investigating a novel area of research focusing on creative design, and incorporating the results into a system model feasible for production use. The model presented is based on the concept of reusing past experience and existing cases to solve future design problems in different application domains. The resulting system performs its task by reasoning and learning by ANALOGY while utilizing the Logical-Building Block approach to design. Our method demonstrates the use of a case-based reasoner in conjunction with other existing techniques, such as heuristic reasoning and first principle reasoning, to produce a system with three levels of reasoning strategies. Such a system will exhibit a learning capability by which its performance is enhanced with repeated use. A prototype has been implemented and tested for the synthesis of various mechanisms

Thermal analysis and bearing capacity of piles embedded in frozen uniform soils

The objective of this research is the analysis of propagation of the thawing front in frozen soils induced by the periodical change of temperature acting on the top boundaries. This problem appears to be important in determination of the maximum depth of thawing zone arising around the piles. The negligence of the thawing depth in analysis of deep foundations embedded in frozen soils leads to excessive settlements and finally can result in very costly repairs of the structures. Consequently, this problem is very important in calculations of the bearing capacity of the piles supporting various structures (e.g. bridge structures). The formulation of the heat transfer problem including phase change for fixed domain is based on the law of conservation of energy. This law determines the weak form of the problem including all possible thermal boundary conditions. After the determination of the maximum depth of thaw defining the active layer, uplift or heaving forces that result from adfreezing on deep foundation in frozen soil are investigated. Laboratory experiments are conducted to estimate the adfreeze bond strength at the side of a pile in contact with a soil sample. (Abstract shortened by UMI.)Dept. of Civil and Environmental Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1994 .A85. Source: Masters Abstracts International, Volume: 34-02, page: 0815. Adviser: Barbara Budkowska. Thesis (M.A.Sc.)--University of Windsor (Canada), 1994

Exploring the cause of injury or death in grain entrapment, engulfment and extrication

Grain entrapments and engulfments are one of most common hazards associated with grain storage facilities. Since the 1970’s over 1,880 incidents have been documented in agricultural confined spaces of which 65% of all recorded incidents were grain entrapments and engulfments. There have been several studies conducted on the contributing factors behind these incidents; however, there have been very few attempts to understand the environmental, physiological or psychological factors the victims experience while entrapped, engulfed, or extricated. This includes understanding how secondary injuries are caused by grain or during extrication by first responders. The research effort was divided into three segments. The first segment is a literature review to identify and better understand the environmental, physiological and psychological stresses that an individual might be exposed to during grain entrapment, engulfment or extrication. The second segment expands upon previous studies that involved vertical pull tests (Schwab, Ross, Piercy, McKenzie, & B.A, 1985; Roberts, Field, Maier, & Stroshine, 2015) by testing forceful extrication attempts under a wider set of variables, including different types of grains (corn, popcorn, wheat, oats, soybeans, canola seeds and sunflower seeds), depths of entrapment, pull angles (15°, 30°, 45°, 60°, and 75°), limb placement and grain moisture content (corn only). With the exception of the pull angle test, these experiments were conducted only in a small scale setting. Pull angle tests were conducted in a full scale setting using a full sized mannequin (185 lb) in corn and soybeans. This is an important study since grain bin roofs are not generally designed for 5,000 lb anchor points. In addition, the tensile force limits of a sheep spine were tested and compared to the force needed to extricate a mannequin. The third segment focused on measuring the actual pressure that a victim might experience by pushing wooden plates against grain (simulating a rib cage pushing against the grain) and measuring the force. These experiments also focused on localized forces on the spine and limbs and estimating forces generated when a test mannequin is extricated at different angles. The literature review provided a total of eleven factors that negatively impact a victim’s ability to survive a grain entrapment. The most important factor was asphyxiation (which includes aspiration, crush asphyxiation and postural asphyxiation). In 33 cases where the cause of death was medically reported, 63% cited asphyxiation. Another factor of notable importance is psychological, where it was found that stress could cause shortness of breath and chest pain and thus could be a contributing factor in death. In the extrication segment of the research, it was found that high moisture content could increase extrication forces by 39%. In addition, while shallow angles of pull did not significantly impact extrication force, pulling a victim at angles sharper than 45o degrees increased extrication forces by 22-44%. Lastly, the author found that the maximum tensile force that a spine can handle (1.65-2.48 kN) was in the same range of forces required to extricate a victim from between waist and shoulder depth. In the third segment of research, the author found that passive pressure on the victim was about four times larger than active pressure, thus a victim will experience four times more pressure in grain (while attempting to breath) than what a load cell measures. In conclusion, the best strategy to prevent or reduce the severity of injuries associated with grain entrapments remains prevention through compliance with accepted best workplace practices and current workplace safety regulations. It was determined that 94% of all grain entrapment and engulfment incidents were preventable. Regarding methods of victim extrication from grain entrapment it was concluded that there is a real and possible risk of causing secondary injuries, including spinal injury, if force is used to pull the victim from the grain. Reducing the pressure on the victim by removing the grain from around the victim is strongly recommended unless there are other significant medical issues that might reduce the likelihood of survival if extrication is not expedited

The Determinants of Dividend Policy: Evidence from Malaysian Firms

The aim of this study is to investigate the relationship between dividend payout ratio in Malaysian firms with profitability, size, growth opportunities, free cash flow, business risk and market to book value. The paper used a sample of 284 firms listed on the Kuala Lumpur Stock Exchange (KLSE) from seven sectors viz., Consumer Products, Industrial Products, Construction, Finance, Technology, Properties, and Telecommunication. In order to decipher the relationships as stated above, multivariate regression analysis is used to test the hypotheses. The study found that at the pooled data level for All sectors, free cash flow, return on assets, return on equity, earning per share, market to book value and market capitalization have significant positive correlation with dividend payout ratio. The variable Beta, however, has a strong negative correlation with dividend payout ratio. The findings however differ from sector to sector; results reflect that Market capitalization; Beta, ROA and ROE are the common variables which have influence on DPR across various sectors except in technology sector where as the variable Market capitalization is not significantly associated with DPR. Similarly, ROA, which is significant determinant variable of DPR in four sectors like Construction, Consumer Products, Properties and Telecommunication Sector, it has no influence on the dividend payout ratio of the companies in the Industrial, Technology and Finance sectors. Keywords: dividend payout ratio, profitability, size, growth opportunities, free cash flow, business risk, market to book value, market capitalization, Beta

Effectiveness of Newly Introduced Variable Message Signs in Al-Khobar, Saudi Arabia

Recently, Variable Message Signs (VMS) were introduced in Saudi Arabia and their reliability under local environment is being tested. This paper aims to evaluate the possible response of the drivers to VMS when used for messages related to traffic conditions. A major arterial in Al-Khobar city in Saudi Arabia with a massive VMS board was selected for this paper. The evaluation process started by interviewing drivers selected randomly from the study area. About 77% of the interviewed drivers indicated positive attitude toward messages requesting change of route. The drivers’ interviews demonstrated statistical relationship between the degree of response to messages requesting change of route and the reason for such request. The maximum response was for messages related to accidents, roadwork activities, and traffic congestion. A field experiment was also conducted along the studied arterial. It was found that VMS statistically increased the percentage of diverted traffic during specific peak periods.</p

Regulated release of BDNF by cortical oligodendrocytes is mediated through metabotropic glutamate receptors and the PLC pathway

A number of studies suggest that OLGs (oligodendrocytes), the myelinating cells of the central nervous system, are also a source of trophic molecules, such as neurotrophins that may influence survival of proximate neurons. What is less clear is how the release of these molecules may be regulated. The present study investigated the effects of BDNF (brain-derived neurotrophic factor) derived from cortical OLGs on proximate neurons, as well as regulatory mechanisms mediating BDNF release. Initial work determined that BDNF derived from cortical OLGs increased the numbers of VGLUT1 (vesicular glutamate transporter 1)-positive glutamatergic cortical neurons. Furthermore, glutamate acting through metabotropic, and not AMPA/kainate or NMDA (N-methyl-d-aspartate), receptors increased BDNF release. The PLC (phospholipase C) pathway is a key mediator of metabotropic actions to release BDNF in astrocytes and neurons. Treatment of OLGs with the PLC activator m-3M3FBS [N-(3-trifluoromethylphenyl)-2,4,6-trimethylbenzenesulfonamide] induced robust release of BDNF. Moreover, release elicited by the metabotropic receptor agonist ACPD [trans-(1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid] was inhibited by the PLC antagonist U73122, the IP3 (inositol triphosphate 3) receptor inhibitor 2-APB (2-aminoethoxydiphenylborane) and the intracellular calcium chelator BAPTA/AM [1,2-bis-(o-aminophenoxy)ethane-N,N,N′,N′-tetra-acetic acid tetrakis(acetoxymethyl ester)]. Taken together, these results suggest that OLG lineage cells release BDNF, a molecule trophic for proximate neurons. BDNF release is regulated by glutamate acting through mGluRs (metabotropic glutamate receptors) and the PLC pathway. Thus glutamate and BDNF may be molecules that support neuron–OLG interactions in the cortex

Ultraviolet and Infrared Spectra of Some p-Nitrobenzyl Phenyl Ethers

The UV-spectra of substituted p-nitrobenzyl phenyl ethers in ethanol and carbon tetrachloride were recorded. The effect of substitution on band position and intensity is correlated with the electronic nature of the group. The IR-spectra are analysed and the position of certain bands ii;; dis.cussed in terms of molecular structure

Building the capacity of agricultural extension personnel for effective implementation of agricultural transformation agenda in Nigeria

This paper reviews the capacity (number, quality and motivation) of the extension personnel in Nigeria; and describes farmers’ perception of the quality of extension service delivery using evidences from literature, reports of organizations as well as experiences from field research. Findings reveal a tremendous shortage in the number and quality of extension personnel across the country as major reason for the poor performance of the ADPs thereby leaving no hope for the “beautiful†transformation agenda. This paper strongly recommends immediate recruitment of new hands as well as full implementation of a well-designed capacity building programme so as to ensure a sustainable extension service delivery system where extension personnel can operate in the expected commercial (agriculture-driven) economy

Building the capacity of agricultural extension personnel for effective implementation of agricultural transformation agenda in Nigeria

This paper reviews the capacity (number, quality and motivation) of the extension personnel in Nigeria; and describes farmers’ perception of the quality of extension service delivery using evidences from literature, reports of organizations as well as experiences from field research. Findings reveal a tremendous shortage in the number and quality of extension personnel across the country as major reason for the poor performance of the ADPs thereby leaving no hope for the “beautiful†transformation agenda. This paper strongly recommends immediate recruitment of new hands as well as full implementation of a well-designed capacity building programme so as to ensure a sustainable extension service delivery system where extension personnel can operate in the expected commercial (agriculture-driven) economy