135 research outputs found
Flexible models for dynamic linking
Get PDFAbstractDynamic linking supports flexible code deployment, allowing partially linked code to link further code on the fly, as needed. Thus, end-users enjoy the advantage of automatically receiving any updates, without any need for any explicit actions on their side, such as re-compilation, or re-linking. On the down side, two executions of a program may link in different versions of code, which in some cases causes subtle errors, and may mystify end-users.Dynamic linking in Java and C# are similar: the same linking phases are involved, soundness is based on similar ideas, and executions which do not throw linking errors give the same result. They are, however, not identical: the linking phases are combined differently, and take place in different order. Consequently, linking errors may be detected at different times by Java and C# runtime systems.We develop a non-deterministic model, which describes the behaviour of both Java and C# program executions. The non-determinism allows us to describe the design space, to distill the similarities between the two languages, and to use one proof of soundness for both. We also prove that all execution strategies are equivalent with respect to terminating executions that do not throw link errors: they give the same results
Investigating the effects of physical and cognitive demands on quality of performance and subjective responses under pacing/ takt time
Get PDFAssembly work requires high levels of performance and quality but may involve complex cognitive and physical tasks. There is evidence that physical and cognitive workloads are not separate, but may interact. Work in exercise and simple physical tasks suggests that physical load may lead to changes in cognitive performance, and in perceived workload. The aim of this thesis is to examine physical and cognitive interactions that might affect assembly work.
First, observation was undertaken in industry to identify the physical and cognitive factors relevant to examples of assembly lines. From this, a task analysis of a simulated assembly task was developed. Three experimental studies were conducted, based upon the simulated assembly task, in order to investigate three main assembly variables; working height, memory load and pacing. The first study showed that the number of completed assemblies was reduced when performed at higher pacing and while working at above shoulder height. The number of components dropped was higher when performed at above shoulder height. When the task was performed at elbow height ‘wait’ time increased as the beep time was found to be higher at elbow height than the above shoulder height, which led to increase wait time when performing the task at elbow height. Subjective measures (NASA TLX) showed that temporal demand and effort were reported as higher during high pacing. Perceived physical and temporal demand increased when working above shoulder height. An interaction on subjective measure was identified between pacing and working height. Performance of NASA TLX was found to be poor when performing the assembly operation at high pacing/Takt and above shoulder height as compared to working at high pacing/ Takt and elbow height.
In the second study the experimental design was modified by changing the assembly order to variable assembly and consistent assembly, which represented single model assembly line (where only one type of assembly is being processed) and mixed model assembly line (different types of products being processed). Study 2 was found to be more mentally demanding due to task complexity. However, it was also found that completed assemblies were higher for the consistent assembly task. Subjective measures reported stress as being higher for higher pacing and variable assembly.
The final study combined the variables from the first two studies as well as investigating different levels of memory load. Performance times for variable assembly were longer and resulted in less correct code responses. A higher memory load resulted in a higher performance time and lower correct code responses as well as fewer completed assemblies. An interaction between working height and perceived mental workload was found. Results showed that perceived temporal demand and perceived effort of NASA TLX were found to be higher when performing the assembly operation at elbow height and high memory as compared to the assembly operation performed at elbow height and low memory. It was also found that memory load affects perceived physical demand.
For industry the findings suggest that in variable (mixed model) assembly different levels of pacing, working height and cognitive demands may affect workers’ performance both physically and mentally. Demands will be higher when working at variable assembly but also performance will vary where variable and consistent assembly are used together. The research also discusses theories that might be most useful for describing these effects
Ion Membrane Channelopathies: A Connected Gateway: Brugada Pattern in a patient with underlying Charcot Marie Tooth Syndrome
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A rare case of myocardial injury in a patient with systemic lupus erythematosus Hydroxychloroquine induced cardiomyopathy
No full textInvestigating the effects of physical and cognitive demands on quality of performance and subjective responses under pacing/ takt time
No full textAssembly work requires high levels of performance and quality but may involve complex cognitive and physical tasks. There is evidence that physical and cognitive workloads are not separate, but may interact. Work in exercise and simple physical tasks suggests that physical load may lead to changes in cognitive performance, and in perceived workload. The aim of this thesis is to examine physical and cognitive interactions that might affect assembly work.
First, observation was undertaken in industry to identify the physical and cognitive factors relevant to examples of assembly lines. From this, a task analysis of a simulated assembly task was developed. Three experimental studies were conducted, based upon the simulated assembly task, in order to investigate three main assembly variables; working height, memory load and pacing. The first study showed that the number of completed assemblies was reduced when performed at higher pacing and while working at above shoulder height. The number of components dropped was higher when performed at above shoulder height. When the task was performed at elbow height ‘wait’ time increased as the beep time was found to be higher at elbow height than the above shoulder height, which led to increase wait time when performing the task at elbow height. Subjective measures (NASA TLX) showed that temporal demand and effort were reported as higher during high pacing. Perceived physical and temporal demand increased when working above shoulder height. An interaction on subjective measure was identified between pacing and working height. Performance of NASA TLX was found to be poor when performing the assembly operation at high pacing/Takt and above shoulder height as compared to working at high pacing/ Takt and elbow height.
In the second study the experimental design was modified by changing the assembly order to variable assembly and consistent assembly, which represented single model assembly line (where only one type of assembly is being processed) and mixed model assembly line (different types of products being processed). Study 2 was found to be more mentally demanding due to task complexity. However, it was also found that completed assemblies were higher for the consistent assembly task. Subjective measures reported stress as being higher for higher pacing and variable assembly.
The final study combined the variables from the first two studies as well as investigating different levels of memory load. Performance times for variable assembly were longer and resulted in less correct code responses. A higher memory load resulted in a higher performance time and lower correct code responses as well as fewer completed assemblies. An interaction between working height and perceived mental workload was found. Results showed that perceived temporal demand and perceived effort of NASA TLX were found to be higher when performing the assembly operation at elbow height and high memory as compared to the assembly operation performed at elbow height and low memory. It was also found that memory load affects perceived physical demand.
For industry the findings suggest that in variable (mixed model) assembly different levels of pacing, working height and cognitive demands may affect workers’ performance both physically and mentally. Demands will be higher when working at variable assembly but also performance will vary where variable and consistent assembly are used together. The research also discusses theories that might be most useful for describing these effects
Pituitary Hyperplasia in a Boy with Van Wyk–Grumbach Syndrome due to Long-standing Hypothyroidism
No full textDesign of a four wheeled autonomous collision avoidance robot
No full textMobile robots are of a different kind, and here we are focusing on Wheeled Mobile Robot (WMR). The robot discussed in this paper is an Autonomous one which will be able to perform its task without the help of a supervisor and keeps on changing its method of completion of task based on the dynamic environment change. The robot is designed with mecanum wheels i.e., an Omni-directional robot, model design is done using Computer-Aided Designing (CAD) software called Solidworks, and the simulation is done in MATLAB. The different tools of MATLAB are used in this paper such that so that the robot follows the shortest path while avoiding collision to reach the destination in the created environment. The robot is placed in two different locations and allowed to simulate to reach the destination. The paper elaborately discusses the control design and implementation of all the discussed methods to make it operative and useful for future applications
Right Ventricular Stress Relief by Intra-Pulmonary Shunting in Portopulmonary Hypertension
No full textThree essays on economics of crime and immigration
No full textIn the United States, immigration policies are politically debated when the concern is about the effect of such policies on crime and labor market outcomes. Even though the concern for crime exists for a long time, such concern is intensified due to rise in crime and the contagious behavior of crime in United Sates. Therefore, the primary objective of this dissertation is to investigate the causal effect of different immigration policies on crime and labor market outcomes in the context of United States. In addition, contagious behavior of crime along with the effects of different socio-economic and socio-demographic factors on crime are also examined in the context of US by allowing for county-level spatial dependence. The first chapter investigates statistically, the sanctuary policy (implemented on different US counties) effect on broad categories (i.e., violent and non-violent crime) and subcategories (i.e., murder, rape, burglary, motor vehicle (MV) theft) of crime from the lens of different causal methods. The analysis is conducted considering US county-level panel data and by applying different variations of difference in differences (DID) and synthetic control methods. A further analysis of sanctuary policy effects on crime is conducted by applying both the methods in a staggered treatment adoption setting. The results found that, even though there are few significant rises in crime categories due to sanctuary policy implementation, most of the results indicate that there is no evidence of statistically significant effect of sanctuary policy on different crime categories.
Chapter two of the dissertation focuses on the contagious/spilling behavior of crime along with investigating the linkages in between violent and non-violent crime in United States. In addition, direct and indirect (i.e., spillover) effects of different socio-economic and socio-demographic factors on violent crime is also analyzed. For analysis, US county-level panel data is used where county-level spatial dependence is allowed among the variables and panel spatial econometric models are applied on the data to capture the spilling behavior. The key findings of this study strikingly suggest that cross-county crime spillover exists where non-violent crime leads to violent crime. In addition, income shows greater effect on violent crime where other socio-economic and socio-demographic variables suggest mixed effects in both short and long run.
In chapter three, immigration policy effect on labor market outcomes is analyzed considering a highly debated immigration policy known as Deferred Action for Childhood Arrivals (DACA). DACA was first announced by President Obama in 2012 which provides work authorization and protection from deportation to “eligible unauthorized immigrants” and there are several criteria to become DACA-eligible. The policy became debatable due to its possible detrimental effects on labor market outcomes of DACA-ineligibles including the citizens of US. Therefore, this chapter primarily investigates the causal effect of DACA on labor market outcomes (i.e., yearly real income, weekly wage, weekly working hours, fraction of week worked in a year) of DACA-eligible individuals via the lens of difference in differences (DID) method. Later, DACA effects on DACA-ineligible’s (including natives) and DACA-eligible’s labor market outcomes are assessed from a DACA induced labor “supply shock” perspective, applying instrumental variable (IV) and least square methods. The key findings suggest positive causal effect of DACA on DACA-eligible individual’s labor market outcomes where DACA-ineligibles face bigger detrimental effects on their labor market outcomes due to DACA induced labor supply shock.Embargo status: Restricted until September 2022. To request an access exception, click on the PDF link to the left
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