426 research outputs found
Antecedents and Consequences of Global Supply Chain Process Integration
Global business executives and researchers recently highlight the importance of understanding the dynamics of supply chain process integration in a global context. The literature still lacks studies that provide a comprehensive understanding of the major antecedents and consequences of supply chain process integration from a global perspective. This dissertation builds on several theoretical foundations such as the resource based view (RBV), the relational view (RV) of the firm and transaction cost analysis (TCA) to develop a framework that explains the drivers and outcomes of global supply chain process integration.
This global study responds to these challenges through exploring the antecedents and consequences of global supply chain process integration for 320 supply chain and purchasing managers that source from over 33 countries. A theoretical framework is proposed that builds on research in strategic management, supply chain management, and international business and tests 8 proposed hypotheses. One new construct – global supply chain process integration – is developed and tested. Another construct, logistics performance, is modified from its existing form in the current literature.
Significant results and good fit indices tested with structural equation modeling generate a number of interesting implications for global supply chain managers and researchers. For executives and strategists who are concerned about better managing their supply chains, this study provides insights for how manufacturing firms can develop a competitive edge through a higher level of flexibility by integrating its supply chain processes with its global suppliers. The study also provides empirical evidence on how supplier flexibility in a global environment can lead to improvements in process and firm performance
Kernel-Based Estimation of P(X less than Y)With Paired Data
A point estimation of P(X \u3c Y) was considered. A nonparametric estimator for P(X \u3c Y) was developed using the kernel density estimator of the joint distribution of X and Y, may be dependent. The resulting estimator was found to be similar to the estimator based on the sign statistic, however it assigns smooth continuous scores to each pair of the observations rather than the zero or one scores of the sign statistic. The asymptotic equivalence of the sign statistic and the proposed estimator is shown and a simulation study is conducted to investigate the performance of the proposed estimator. Results indicate that the estimator has a good overall performance
Solving Modal Equations of Motion with Initial Conditions Using MSC/NASTRAN DMAP
By utilizing MSC/NASTRAN DMAP (Direct Matrix Abstraction Program) in an existing NASA Lewis Research Center coupled loads methodology, solving modal equations of motion with initial conditions is possible using either coupled (Newmark-Beta) or uncoupled (exact mode superposition) integration available within module TRD1. Both the coupled and newly developed exact mode superposition methods have been used to perform transient analyses of various space systems. However, experience has shown that in most cases, significant time savings are realized when the equations of motion are integrated using the uncoupled solver instead of the coupled solver. Through the results of a real-world engineering analysis, advantages of using the exact mode superposition methodology are illustrated
Solving modal equations of motion with initial conditions using MSC/NASTRAN DMAP. Part 1: Implementing exact mode superposition
Within the MSC/NASTRAN DMAP (Direct Matrix Abstraction Program) module TRD1, solving physical (coupled) or modal (uncoupled) transient equations of motion is performed using the Newmark-Beta or mode superposition algorithms, respectively. For equations of motion with initial conditions, only the Newmark-Beta integration routine has been available in MSC/NASTRAN solution sequences for solving physical systems and in custom DMAP sequences or alters for solving modal systems. In some cases, one difficulty with using the Newmark-Beta method is that the process of selecting suitable integration time steps for obtaining acceptable results is lengthy. In addition, when very small step sizes are required, a large amount of time can be spent integrating the equations of motion. For certain aerospace applications, a significant time savings can be realized when the equations of motion are solved using an exact integration routine instead of the Newmark-Beta numerical algorithm. In order to solve modal equations of motion with initial conditions and take advantage of efficiencies gained when using uncoupled solution algorithms (like that within TRD1), an exact mode superposition method using MSC/NASTRAN DMAP has been developed and successfully implemented as an enhancement to an existing coupled loads methodology at the NASA Lewis Research Center
Study of Lateral Load Influence on Behaviour of Negative Skin Friction on Circular and Square Piles
Negative skin friction developed on the pile surface causes many problems when piles are built in fully saturated clay. In this work, a study of NSF on a square cross-section pile corresponding to the circular pile circumference was developed. The pile was modeled as a concrete element, embedded and fully contacted with fully saturated soft clay. The clay layer is supported on a sand layer as a sub-base using ABAQUS software, and the NSF was developed on piles due to the consolidation of the clay over a 5-year period. A square pile has been found to provide lower NSF values than a round pile. Then, for the first investigation, both piles were loaded with lateral loads at the top to investigate the effect of the horizontal load on the NSF values, as there is no literature or study done on this point. The results emphasized that lateral loads reduce the NSF developed on piles. A parametric study was performed to investigate the parameters affecting the NSF values induced on piles, such as soil permeability, ballast, and lateral load values. It was concluded that square piles provide better NSF values than round piles for both single piles and pile groups. Doi: 10.28991/CEJ-2022-08-10-08 Full Text: PD
Citric acid strongly inhibits visceral pain response in mice
Citric acid introduced into the stomach of mice at increasing concentrations of 0.1, 1 or 10 %
(4.8 µM-0.48 mM; 95 µmol/kg-9.5 mmol/kg, 0.5 ml) caused dose-dependent inhibition of
abdominal constrictions induced 1 h later by i. p. acetic acid injection by -51 % to -69.5 %.
When administered at 10 % (0.48 mM, 0.5 ml) 15 min before nociceptive challenge, citric
acid inhibited the nociceptive response by 96.8 %. Inhibition of the acetic acid-induced abdominal
constrictions was also observed when lower doses of citric acid were introduced into
the stomach (0.2 ml of 0.1-1 %; 38.1 µmol/kg-0.38 mmol/kg). The effect was evident as early
as 5 min after administration of citric acid into the stomach and with the maximal effect being
at 15-30 min after dosing. Lidocaine given orally 5 min prior to citric acid (1 %, 48 µM;
0.38 mmol/kg, 0.2 ml) prevented antinociception by citric acid, but lidocaine given 15 min
before oral introduction of citric acid enhanced the citric acid-induced inhibition of the nociceptive
response to acetic acid. The antinociceptive effect of orally administered citric acid
(1 %, 48 µM; 0.38 mmol/kg, 0.2 ml) was increased by pre-treatment with propranolol
(4 mg/kg, s. c.), yohimbine (4 mg/kg, s. c.), guanethidine (32 mg/kg, s. c.), but reduced after
treatment with atropine (3 mg/kg, s. c.), which itself increased the nociceptive behavior. Similar
inhibition of the acetic acid-induced nociceptive behavior was also observed when sodium
citrate (pH 7.21) or 0.1 N HCl (pH 3) or 1 % sucrose solution (0.2 ml) was intragastrically
given. It is suggested that citric acid might act to stimulate sensory afferents and that transmission
of nociceptive information centrally leads to the activation of descending antinociceptive
mechanism to a noxious stimulus
West Texas Intermediate and Brent Spread during Organization of the Petroleum Exporting Countries Supply Disruptions
This paper investigates the price spread between West Texas Intermediate and Brent during periods of supply disruptions. Using a sample of 50 events of Organization of the Petroleum Exporting Countries (OPEC) - related unplanned upstream production outages, this paper documents a statistically significant tightening in the price differential. The finding is robust even after accounting for 22 OPEC - related political conflicts, 104 extreme weather conditions in the Atlantic basin, and the period of infrastructural bottlenecks in and around the Cushing, Oklahoma. The result is further confirmed when examining the spread between Light Louisiana sweet and Brent. These findings suggest the need to hedge against such risks and give rise to speculative trading which can be facilitated using the vibrant paper markets.
Keywords: Crude Oil, Benchmarks, Organization of the Petroleum Exporting Countries, Supply Disruptions
JEL Classifications: G12, Q34, Q4
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Face Detection Using Single Cascade of Customized Features Discriminators
Face detection has become an important and helpful tool for camera and video processing. Useful human-computer interaction (HCI) applications such as drivers assistant system that prevents accidents and saves pedestrian lives when drivers attention is absent, needs a head pose estimator. A head pose estimator cannot function without face detector.
There has been a considerable amount of literature to address the problem. The most significant results obtained on uptight frontal face detection which is a sub-problem of a larger problem of face detection. There are other types of sub-problems that has been studied with least significant advancements that the upright frontal face detection had accomplished. The problem of multi-pose detection is still under study and it remains hard.
A solution to this large scale of the problem (multi-pose face detection) is critical in head pose accuracy. This thesis suggests a multi-pose face detection algorithm for uncontrolled environments. The detector is designed to be used in building head pose estimator for a human-computer interaction application. The observed design of the detector has to implement a cascade of classifiers. Each classifier has to address at least one certain area of the problem. The design have to maintain speed and an acceptable detection rate.
These requirements can be satisfied by constructing the cascade to implement fast and simple classifiers at first stages of the cascade. A novel use of the integral image as a fast filter was invented to be placed at the start of the detection process. Included in the cascade, classifiers that are trained on special designed features aimed to solve part of the problem. One special unique classifier is a data mining based classifier that uses a modified version of the Maximal Frequent Itemset Algorithm (MAFIA) [2] for feature extraction.
Special features classifiers use the extracted facial features information extracted from a new knowledge-based classifier/filter that was created with the capacity to locate to an acceptable ac- curacy the location of eyes, mouth and nose using a suite of approaches including discreet local minima and geometric measures. The extracted facial features were used to estimate head pose and extract classifier features accordingly to enhance detection rates.
A cascade of classifiers based on fast and simple contrast features was used to refine and speed up the detection process. To further improve speed some components were parallelized. As an attempt to overcome some of the fundamental challenges of face detection, lighting correction and noise reduction were implemented based on the information extracted from images.
Results are reported on the FDDB [12] benchmark showed 5.22% detection rate with 2000 false positives while OpenCV implementation of Viola-Jones [19] face detector showed 65.92 detection rate with 2010 false positives. This comparison is flawed; because Viola-Jones is an upright face detector and even though FDDB [12] includes a number on non-frontal faces and profiles the majority of the faces are frontal. The two solutions address two different problems that reflect large differences in difficulty.
A standard benchmark testset and evaluation system as FDDB [12] benchmark and com- parable results from the same class of the problem at the time of writing this document was not available. The key points to building good face detector in general are; (1) resolving speed issues using fast techniques (e.g. integral image) at the start of the cascade and a powerful design, (2) using a huge number of different strong and weak features, and (3) eliminating variations (i.e. pose , noise and lighting variations). The algorithm was also tested on MIT+CMU upfront faces testset and reported 43.56% detection rate with 504 false positives
Response of Polycrystalline Solar Cell Outputs to Visible Spectrum and other Light Sources-a Case Study
In this case study, two polycrystalline solar modules were installed outdoors (irradiated by sunlight) and indoors (irradiated by artificial lights). The solar cells in both cases were installed using different color filters that allowed the passage of certain light frequencies. The amount of energy produced by each module were measured and compared to a reference module with no filter. The results indicated the variable response of polycrystalline solar cells to natural and artificial light sources, being more responsive in both cases to red band color as could be deduced from their % current outputs (72.5% sunlight radiation; 84.38% artificial light sources). Other colors, including yellow, green, orange and violet afforded acceptable outputs. The results indicated that electrical outputs of indoor solar cells decreased when colored filters were used, but red filter in general afforded the maximum outputs, for both the artificially radiated indoor and naturally radiated outdoor solar cells. The case study suggests the possible complementary advantage of using indoor mounted solar cells for the production of electricity during artificial illumination period of the day
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