Decision Analysis Essay Example for Free

Decision Analysis Essay Finally, some typical problem classes are examined and some requirements for prototypical structures are discussed. An introduction to problem structuring Decision analysis can be divided into four steps: structuring the problem; formulating inference and preference models; eliciting probabilities and utilities; and exploring the numerical model results. Prac* This research was supported by a grant from the Department of Defense and was monitored by the Engineering Psychology Programs of the Office of Naval Research, under contract While writing this paper, the author discussed the problem of structuring extensively with Helmut Jungermann. The present version owes much to his thought. Please don’t take footnote 3 too seriously. It is part of a footnote war between Ralph Keeney and me. ** Presently with the Social Science Research Institute, University of Southern California, University Park, Los Angeles, CA 90007, (213) 741-6955. 12 D. von Winterfeldt /Structuring decision problems titioners of decision analysis generally agree that structuring is the most important and difficult step of the analysis. Yet, until recently, decision analytic research has all but ignored structuring, concentrating instead on questions of modeling and elicitation. As a result, structuring was, and to some extent still is, considered the ‘art’ part of decision analysis. This paper examines some attempts to turn this art into a science. Trees are the most common decision analytic structures. Decision trees, for example, represent the sequential aspects of a decision problem (see Raiffa 1968; Brown et al. 1974). Other examples are goal trees for the representations of values (Keeney and Raiffa 1976) and event trees for the representation f inferential problem aspects (Kelly and Barclay 1973). In fact, trees so much dominate decision analytic structures that structuring is often considered synonymous to building a tree.

Causes of Epilepsy and Seizures

Causes of Epilepsy and Seizures Contents (Jump to) Introduction to Epilepsy Seizures Causes of Epilepsy Conclusion References Figures Appendix Introduction to Epilepsy Epilepsy is the oldest known brain disorder dating back as early as 2080BC (Cascino et al., 1995). It was first identified as a disease by Dr Jon Hughlings Jackson in 1880 who defined it as â€Å"An occasional, sudden, massive, rapid and local discharge or the grey matter† (Scott, 1978). This definition has been confirmed 50 years later by Electroencephalography. A more recent definition was devised stating â€Å"Epilepsy is a neurological disorder in which the nerve cell activity in your brain is disturbed, causing a seizure during which you experience abnormal behaviour, symptoms and sensations, including loss of consciousness.†(Scambler, 1989) Worldwide, it is estimated that there are 65 million people living with epilepsy with almost 80% of the cases reported occurring in the developing world (Ngugi et al., 2010). Within the UK, the prevalence is between 1 in 40/70,000 which equates to 3% of the population will develop epilepsy in their lifetime. Recurrent seizures are the hallmark characteristic of an epileptic. If an individual has one seizure early in their lives then none thereafter, they are said to have had an epileptic seizure but do not suffer from epilepsy. (Duncan et al., 2006) Seizures A seizure is abnormally excessive neuronal activity localised to a particular area of the brain known as the cerebral cortex causing a disruption to normal brain function. These cortical discharges will transmit to the muscles causing convulsions or commonly referred to as a fit. Figure 1 Generalised seizure with neuronal activation in both hemisphere Classifying seizures is done based on the site of the brain which the seizure begins. This will be either; Partial – where the onset of seizure is localised to one part of the hemisphere (fig. 1), Generalised – where the onset of the seizure is across both hemispheres (fig. 2) or Secondary generalised – where a partial seizure later spreads to involve the majority of the 2 cerebral hemispheres (Duncan et al., 2006). Figure 2 Partial seizure with neuronal activation in one hemisphere The International League Against Epilepsy (ILAE) have defined 6 main types of seizures: Clonic, Tonic, Tonic-Clonic, myoclonic, absence and atonic (Solodar, 2014), with all having the shared characteristic of syncope. Tonic-clonic seizures (grand mal seizures) are the most common and typically last 30 seconds with an initial back arching motion (tonic phase), followed by severe shaking of body limbs (clonic phase) in which sufferers can become incontinent and bit their tongue (fig. 3). Myoclonic seizures consist of muscle spasms throughout the body, while absence seizures only display mild symptoms such as a slight head turn or repetitive eye blinking (Engel and Pedley, 2008). Figure 3 Tonic and Clonic phases of a seizure Causes of Epilepsy Majority of cases are termed idiopathic, meaning there is no known reason for the disorder in that individual. The difference in causes amongst the general population can be seen in figure 4. Genetic factors can causes epilepsy as can environmental factors. In general it is a combination of the two which go on to cause someone to become epileptic. Over 500 genes have been identified to be linked to the disorder if mutated with some making individuals more sensitive to environmental conditions that can initiate seizures (Sanchez-Carpintero Abad et al., 2007). Some symptomatic causes of epilepsy include; brain tumours, strokes, low oxygen during birth, head injuries during birth or during a person’s lifetime, infections such as meningitis or anything which causes damage to the brain (Chang and Lowenstein, 2003). Figure 4 Causes of epilepsy amongst the general population Conclusion Epilepsy is a condition which has a host of causes as have been highlighted. It is the category of seizure within the brain an individual has which will determine the type of seizure they have and the altered body state which is displayed. This can be a very distressing disorder for sufferers as they are unable to control when they have a seizure and could occur at a very dangerous time such as whilst driving. The effective management via medication, surgery or lifestyle changes can reduce a person’s chance of suffering future seizures. Unfortunately in the majority of cases, the cause is unknown. This makes it highly difficult to target the disease for a cure, therefore minimising the probability of a seizure is the next best thing. References CASCINO, G., HOPKINS, A. O. SHORVON, S. D. 1995. Epilepsy, London, Chapman Hall Medical. CHANG, B. S. LOWENSTEIN, D. H. 2003. Epilepsy. N Engl J Med, 349, 1257-66. DUNCAN, J. S., SANDER, J. W., SISODIYA, S. M. WALKER, M. C. 2006. Adult epilepsy. Lancet, 367, 1087-100. ENGEL, J., JR. PEDLEY, T. A. 2008. Epilepsy : a comprehensive textbook, Philadelphia, Pa. ; London, Wolters Kluwer/Lippincott Williams Wilkins. NGUGI, A. K., BOTTOMLEY, C., KLEINSCHMIDT, I., SANDER, J. W. NEWTON, C. R. 2010. Estimation of the burden of active and life-time epilepsy: a meta-analytic approach. Epilepsia, 51, 883-890. SANCHEZ-CARPINTERO ABAD, R., SANMARTI VILAPLANA, F. X. SERRATOSA FERNANDEZ, J. M. 2007. Genetic causes of epilepsy. Neurologist, 13, S47-51. SCAMBLER, G. 1989. Epilepsy, London, Tavistock / Routledge. SCOTT, D. 1978. About epilepsy, London, Duckworth. SOLODAR, J. 2014. Commentary: ILAE Definition of Epilepsy. Epilepsia, 55, 491. Figures ENGEL, J., JR. PEDLEY, T. A. 2008. Epilepsy : a comprehensive textbook, Philadelphia, Pa. ; London, Wolters Kluwer/Lippincott Williams Wilkins. – figures 1 2 http://www.doctortipster.com/10291-generalized-tonic-clonic-epilepsy-seizures-grand-mal-seizures-clinical-presentation.html figure 3 http://www.cureepilepsy.org/egi/about.asp figure 4 Appendix Reference Type: Book Record Number: 1988 Author: Cascino, Gregory, Hopkins, Anthony October and Shorvon, S. D. Year: 1995 Title: Epilepsy Place Published: London Publisher: Chapman Hall Medical Edition: 2nd ed / edited by Anthony Hopkins, Simon Shorvon and Gregory Cascino. Short Title: Epilepsy ISBN: 0412543303 :  ¹95.00 Accession Number: b9561325 Call Number: 616.853 20 British Library DSC 95/22799 British Library STI (B) GV 05 blsrissc Keywords: Epilepsy. Notes: GB9561325 bnb 2362 Previous ed.: 1987. Includes bibliographies and index. Research Notes: Useful book, especially for historical aspects. Uses different terminology for seizures than other material, possibly due to age of print Reference Type: Journal Article Record Number: 2037 Author: Chang, B. S. and Lowenstein, D. H. Year: 2003 Title: Epilepsy Journal: N Engl J Med Volume: 349 Issue: 13 Pages: 1257-66 Epub Date: 2003/09/26 Date: Sep 25 Short Title: Epilepsy Alternate Journal: The New England journal of medicine ISSN: 0028-4793 DOI: 10.1056/NEJMra022308 Accession Number: 14507951 Keywords: Cerebral Cortex/pathology/physiopathology Electroencephalography Epilepsy/classification/etiology/pathology/*physiopathology Hippocampus/pathology Humans Ion Channels/physiopathology Neuroglia/physiology Sclerosis Thalamus/physiopathology Notes: 1533-4406 Chang, Bernard S Lowenstein, Daniel H NS39950/NS/NINDS NIH HHS/United States Journal Article Research Support, U.S. Govt, P.H.S. Review United States N Engl J Med. 2003 Sep 25;349(13):1257-66. Research Notes: Good overview of the disorder with relevant sections around the causes Author Address: Comprehensive Epilepsy Center, Department of Neurology, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, USA. Database Provider: NLM Language: eng Reference Type: Journal Article Record Number: 10337 Author: Duncan, J. S., Sander, J. W., Sisodiya, S. M. and Walker, M. C. Year: 2006 Title: Adult epilepsy Journal: Lancet Volume: 367 Issue: 9516 Pages: 1087-100 Epub Date: 2006/04/04 Date: Apr 1 Short Title: Adult epilepsy Alternate Journal: Lancet ISSN: 0140-6736 DOI: 10.1016/s0140-6736(06)68477-8 Accession Number: 16581409 Keywords: Adult Aged Anticonvulsants/adverse effects/*therapeutic use Drug Resistance/*genetics Electroencephalography *Epilepsy/diagnosis/drug therapy/physiopathology Humans Incidence Infant Pharmacogenetics Abstract: The epilepsies are one of the most common serious brain disorders, can occur at all ages, and have many possible presentations and causes. Although incidence in childhood has fallen over the past three decades in developed countries, this reduction is matched by an increase in elderly people. Monogenic Mendelian epilepsies are rare. A clinical syndrome often has multiple possible genetic causes, and conversely, different mutations in one gene can lead to various epileptic syndromes. Most common epilepsies, however, are probably complex traits with environmental effects acting on inherited susceptibility, mediated by common variation in particular genes. Diagnosis of epilepsy remains clinical, and neurophysiological investigations assist with diagnosis of the syndrome. Brain imaging is making great progress in identifying the structural and functional causes and consequences of the epilepsies. Current antiepileptic drugs suppress seizures without influencing the underlying t endency to generate seizures, and are effective in 60-70% of individuals. Pharmacogenetic studies hold the promise of being able to better individualise treatment for each patient, with maximum possibility of benefit and minimum risk of adverse effects. For people with refractory focal epilepsy, neurosurgical resection offers the possibility of a life-changing cure. Potential new treatments include precise prediction of seizures and focal therapy with drug delivery, neural stimulation, and biological grafts. Notes: 1474-547x Duncan, John S Sander, Josemir W Sisodiya, Sanjay M Walker, Matthew C Journal Article Research Support, Non-U.S. Govt Review England Lancet. 2006 Apr 1;367(9516):1087-100. Research Notes: Very good overview with clear explanation around neuronal activity of seizures Author Address: Department of Clinical and Experimental Epilepsy, Institute of Neurology UCL, Queen Square, London WC1N 3BG, UK. [emailprotected] Database Provider: NLM Language: eng Reference Type: Book Record Number: 10529 Author: Engel, Jerome, Jr. and Pedley, Timothy A. Year: 2008 Title: Epilepsy : a comprehensive textbook Place Published: Philadelphia, Pa. ; London Publisher: Wolters Kluwer/Lippincott Williams Wilkins Pages: 2797 Edition: 2nd ed. Short Title: Epilepsy : a comprehensive textbook ISBN: 9780781757775 (set) :  ¹173.00 0781757770 (set) :  ¹173.00 Call Number: 616.853 22 British Library DSC m07/.34665 vol. 1 British Library STI (B) 616.853 British Library DSC m07/.34666 vol. 3 British Library DSC m07/.34664 vol. 2 Keywords: Epilepsy. Notes: GBA771698 bnb editors, Jerome Engel Jr., Timothy A. Pedley ; associate editors, Jean Aicardi [et al.]. Previous ed. : c1998. Includes bibliographical references and index. Formerly CIP. Uk Research Notes: Had everything covered in good detail. Reference Type: Journal Article Record Number: 10335 Author: Ngugi, Anthony K., Bottomley, Christian, Kleinschmidt, Immo, Sander, Josemir W. and Newton, Charles R. Year: 2010 Title: Estimation of the burden of active and life-time epilepsy: a meta-analytic approach Journal: Epilepsia Volume: 51 Issue: 5 Pages: 883-890 Short Title: Estimation of the burden of active and life-time epilepsy: a meta-analytic approach ISSN: 0013-9580 DOI: 10.1111/j.1528-1167.2009.02481.x Abstract: To estimate the burden of lifetime epilepsy (LTE) and active epilepsy (AE) and examine the influence of study characteristics on prevalence estimates. Notes: 10.1111/j.1528-1167.2009.02481.x Research Notes: Only really useful for prevalence related material URL: http://dx.doi.org/10.1111/j.1528-1167.2009.02481.x Name of Database: READCUBE Reference Type: Journal Article Record Number: 11373 Author: Sanchez-Carpintero Abad, R., Sanmarti Vilaplana, F. X. and Serratosa Fernandez, J. M. Year: 2007 Title: Genetic causes of epilepsy Journal: Neurologist Volume: 13 Issue: 6 Suppl 1 Pages: S47-51 Date: Nov Short Title: Genetic causes of epilepsy Alternate Journal: The neurologist ISSN: 1074-7931 (Print) 1074-7931 (Linking) DOI: 10.1097/NRL.0b013e31815bb07d Accession Number: 18090951 Keywords: Animals Cerebral Cortex/physiopathology Epilepsy/*etiology/*genetics/pathology Humans Ion Channel Gating/genetics Ion Channels/genetics/*physiology Abstract: BACKGROUND: The contribution of genetic factors to the origin of different epilepsies is a fact established by epidemiological, clinical, and molecular studies. These studies have made it possible to identify numerous mutations in different genes that cause or predispose to the development of certain types of epilepsy. REVIEW SUMMARY: The study of single-gene epilepsies has contributed relevant data regarding the pathophysiology of epilepsy. Most of these genes encode voltage- or ligand-gated ion channels. Other single-gene epilepsies are related to mutations that provoke alterations in neuronal maturation and migration during embryonic development. Nevertheless, the most common forms of epilepsy are not caused by single mutations but by a combination of polymorphisms, most of which are unknown, that generate an alteration in neuronal excitability. In some syndromes, genetic alterations and their consequences have made it possible to explain the therapeutic response to diff erent drugs. Therefore, the progress being made in genetics is changing the classification and diagnosis of epilepsy; moreover, it can sometimes influence the choice of treatment. CONCLUSION: The advances made in genetic knowledge of epilepsy have led to the description of new epilepsy syndromes and to a better characterization of known ones. However, the genes responsible for the most common forms of idiopathic epilepsy remain mostly unknown. This means that for the time being, in clinical practice, genetic diagnosis is limited to uncommon syndromes and to cases in which treatment decisions or genetic counseling can be derived from the diagnosis. Notes: Sanchez-Carpintero Abad, Rocio Sanmarti Vilaplana, Francesc X Serratosa Fernandez, Jose Maria eng Research Support, Non-U.S. Govt Review 2008/01/26 09:00 Neurologist. 2007 Nov;13(6 Suppl 1):S47-51. doi: 10.1097/NRL.0b013e31815bb07d. Research Notes: Very complicated to read. Poorly illustrated. URL: http://www.ncbi.nlm.nih.gov/pubmed/18090951 Author Address: Pediatric Neurology Unit, Department of Pediatrics, Clinica Universitaria de Navarra, Pamplona, Spain. [emailprotected] Reference Type: Book Record Number: 2015 Author: Scambler, Graham Year: 1989 Title: Epilepsy Place Published: London Publisher: Tavistock / Routledge Short Title: Epilepsy ISBN: 0415017580 (pbk) : No price 0415017572 (cased) : No price Accession Number: b8920431 Call Number: 362.1/96853 19 British Library DSC 89/23194 British Library HMNTS YK.1989.a.5440 Keywords: Epileptics Psychology. Notes: GB8920431 bnb 2054 Graham Scambler. The Experience of illness Bibliography: p124-130. _ Includes index. Research Notes: Written with the patient in mind but lacks specific scientific data Reference Type: Book Record Number: 2011 Author: Scott, Donald F. Year: 1978 Title: About Epilepsy : revised Edition Place Published: [S.l.] Publisher: Duckworth Edition: 3rd Ed. Short Title: About Epilepsy : revised Edition ISBN: 0715609467 Call Number: British Library DSC 79/5721 Research Notes: Very well written with good scientific data to back up claims. Reference Type: Journal Article Record Number: 10484 Author: Solodar, J. Year: 2014 Title: Commentary: ILAE Definition of Epilepsy Journal: Epilepsia Volume: 55 Issue: 4 Pages: 491 Date: Apr Short Title: Commentary: ILAE Definition of Epilepsy Alternate Journal: Epilepsia ISSN: 1528-1167 (Electronic) 0013-9580 (Linking) DOI: 10.1111/epi.12594 Accession Number: 24731170 Keywords: *Advisory Committees Epilepsy/*classification/*diagnosis Female Humans Male *Research Report *Societies, Medical Notes: Solodar, Jessica eng Comment 2014/04/16 06:00 Epilepsia. 2014 Apr;55(4):491. doi: 10.1111/epi.12594. Epub 2014 Apr 14. URL: http://www.ncbi.nlm.nih.gov/pubmed/24731170 Research Notes: Good summary of definitions around seizures and all terminology within epilepsy 1

Graphical User Interface For The 3 Axis Cnc Milling Machine Computer Science Essay

Graphical User Interface For The 3 Axis Cnc Milling Machine Computer Science Essay This paper details the design and development of a Graphical User Interface for the 3-Axis CNC Milling Machine, which was designed in-house for testing and research purposes at the University of the South Pacific. The 3-axis CNC Milling Machine used COM Port terminal software, TeraTerm to communicate with the electronics hardware via RS232 link. The GUI was developed using Microsoft ® Visual Basic 2008 Integrated Development Environment. The end result is an interface that is user friendly and is capable of controlling various tasks of the Milling Machine. This paper aims to explain how simple components of Microsoft ® Visual Basic 2008 has been used to design a Windows ® based user interface which is capable of complete control of CNC milling machine. Keywords: GUI, Serial Port, CNC, G Codes, STEP NC 1. INTRODUCTION Over the years a number of methods have been developed to control machine tools. The most widespread used throughout the industry is the G Code language for NC machine tools programming. It is based on the data model stipulated by ISO6983, and has been used for over 50 years [1]. G codes, however, limits the usage of todays fast evolving high-performance hardware [2]. The latest development in NC machine tools programming is ISO 14649 or STEP NC. It is a new standard for data transferring between CAD/CAM systems and CNC machines. It remedies the shortcomings of ISO 6983 by specifying the machining processes rather than machine toolmotion by means of Workingstep, as the basic entity [1] Whichever method of programming NC machine tools is used, it is always important to verify the program before doing actual testing. Verification of NC part programs using a PC is inexpensive compared to testing on model parts. Cutting simulation as a means of testing and verifying NC cutting paths has become an important part of modern machining [3]. With the latest advancements in PC technology and 3D graphics it is much easier to simulate NC cutting paths. A common CNC executes G-code programs, which are generated as a result of planning and scheduling in CAM tools [4]. However an interface is required to send or execute NC part program to the CNC. The user interface is the communication Tool between the operator and the PC-based CNC drilling machine, via the computer screen [5]. The recent advancement in software development technology using Object Oriented Programming (OOP) has made it possible to create simple user interface with a sound communication link to control NC machines. In 2002 [5], a GUI was developed at the University of the South Pacific for a PC-Based computer numeric control drilling machine. The platform for the graphical user interface (GUI) was written in Borlands new rapid application product, C++ Builder ®. Gordon and Hillery [6] developed a Windows ® based graphical user interface for their CNC cutting machine. The user interface communicated with the machine via RS232 serial link. The programming environment used was Borland C++ Builder 3, which allowed the visual development of the program interface. The user interface developed also had features for homing the three axes, editing of NC part program (G Codes) and also previewing the two dimensional cutter motion. This paper mainly focuses on the design of the Graphical User Interface (GUI) for the 3-Axis CNC milling machine. The user interface has been designed in Microsoft ® Visual Basic 2008 Integrated Development Environment (IDE). The features of the GUI are explained in detail. 2. OVERVIEW OF CNC MILLING MACHINE The CNC Milling Machine was designed in-house at the School of Engineering and Physics (SEP) at the University of the South Pacific (USP), for testing and research purposes. It uses an absolute three dimensional coordinate system to create its tool path. It sequentially passes instructions which are in the form of three dimensional coordinates to the Milling Machine for controlling the tool, similar to how G Codes are used. The operational framework of the CNC milling machine is shown in Figure 2.1. It consists of a dedicated PC running Graphical User Interface Software which is used to upload a text file containing X, Y and Z coordinates. It also has features to control the milling operations and to get a two dimensional cutter path preview. The software is linked to the electronics hardware via RS232 serial link. Figure 2.1 Operational framework of the CNC Milling Machine The current CNC Milling machine is only capable of linear interpolation (G01), in terms of G Codes, or moving linearly from one point in the three dimensional space to the next point. To mill different geometries other than straight lines the milling machine has to be given a number of coordinate points which can be used to approximate that particular geometry. For instance to mill a curve the milling machine needs to be given a set of points which lie on the curve. Similar method was used by Min-Yang Yang and Won-Pyo Hong [7] in their three dimensional linear interpolation algorithm. The CNC Milling Machine uses an absolute three dimensional coordinate system (X, Y, and Z) for its tool path generation. The three dimensional coordinates are defined in a text file. Each of the three coordinates has three characters in the text file for instance the X coordinate 0 is defined as 000 in the text file. The Basic Length Unit (BLU) is in millimeters. The electronics architecture of the CNC milling machine consisted of five PIC microcontrollers (PIC16F877) in a distributed architecture, with one master controller and several slave controllers. The master controller of the CNC Milling Machine consists of a PIC16F877 microcontroller which is responsible for coordinating and controlling the overall operations of the Machine. It is the central intelligence system of the CNC Milling Machine. It receives its commands from the user through a user interface and commands other co PIC16F877 Microcontrollers in a distributed architecture to carry out their respective tasks. The mechanical hardware consists of three stepper motors which drive the three axis of the CNC Milling Machine. It also has a 24V DC Motor which is the spindle motor. The worktable consists of clamps to clamp the workpiece firmly on the worktable. For feedback, the machine constitutes of limit switches which control the limit of the worktable. 3. USER INTERFACE Until recently, the CNC machine was using COM port terminal software, TeraTerm, to communicate with Master Controller via RS232 link. The GUI was designed to provide a user friendly interface instead of typing coordinates in TeraTerm. The GUI was designed using Microsoft ® Visual Basic 2008 and coded in BASIC (Beginners All purpose Symbolic Instruction Code). The overall design of the main form of the user interface is shown in Figure 3.1. Figure 3.1 Main form of the GUI It was decided to incorporate the following features in the GUI Opening of text file which contains the coordinates. Previewing of coordinate file (or tool path) in two dimensional X and Y axis Communication with the CNC Machine via RS232 link Milling control features such as homing, manual jog etc Displaying coordinate file 3.1 File Input The GUI contains a MenuStrip at the top of the main form on which there are three menus, File, Setup and Help. The File menu contains an Open menu which opens a file browser window as shown in Figure 3.1.1. The software utilizes an OpenFileDialog control of Visual basic 2008 to prompt the user for the files path. It allowed the user to choose which text file to open in the program. The OpenFileDialog control contains the Filter property which was used to control the type of file to be opened in the program. The only extension allowed was the *.txt. The ShowDialog() method was used to display the Open Coordinate File dialog box on the screen. The FileName property was used to get the path specified by the user. The dialog box is shown in figure 3.1.1 Figure 3.1.1 Open Coordinate File dialog box After getting the path from the user, the program used a FileOpen() function to open the file specified by the user. The end of file function, EOF() was used to iterate through the file until the no more coordinates are left. The LineInput() function was used get a line of coordinates into a string variable. This string variable was then extracted to get the X, Y and Z coordinates in a separate array. The array containing the X, Y and Z coordinate was then used later to generate two dimensional previews and to send to the CNC milling machine. Finally the FileClose() function closes the text file. 3.2 Tool Path Preview The graphical user interface that is designed also contains a two dimensional preview feature which can be used to preview the path taken by the milling tool on the workpiece. The GUI uses the system.drawing.graphics namespace to create tool path. The preview panel, as shown in figure 3.2.1, gives a two dimensional (X, Y) preview of the tool path which will be followed by the cutting tool. It is also to check and verify that the input text file does not contain errors. A Preview command button is used to generate preview. This is activated only when a valid coordinate file is loaded. The GUI utilizes system.drawing namespace which includes system.drawing.graphics class to draw the preview. The DrawLines() method was used to draw a series of lines according to the X and Y coordinates in the coordinate file. Figure 3.2.1 Tool Path Preview control The use of three-dimensional absolute coordinate system has made the previewing algorithm much easier since the preview is two dimensional (X, Y), the program utilizes these X and the Y coordinates to draw a preview of the shape in the preview panel. Once the Preview command button is clicked, the btnPreview_Click event procedure gets the array containing the X and Y coordinates which was previously read from the text file. The procedure then used these coordinates as points to draw a series of lines using the DrawLines() method. Since absolute coordinates are used, the lines connect from the end point of the first X, Y coordinate to the start point of the next X, Y coordinate. In this way the path taken by the cutter is drawn by connecting the series of points. 3.3 Milling Controls The GUI on the main form contained a group box with a number of command buttons for commanding the milling machine. The Home command button was used to command the milling machine to rapidly move to its home position. Figure 3.3.1 Milling Control panel The advantage of using a software interface to control the CNC Milling Machine is that it acts like a control panel of the CNC which resides on the PC. Several command buttons have been used on the main form to command the CNC Milling Machine to carry out various tasks. The Home command button is used to command the CNC Milling Machine to move to its home position. The milling control also contains a command button Start to run or to send the coordinates to the milling machine to start milling. The flowchart in figure 3.3.2 shows this. Figure 3.3.2 Flowchart showing the start subroutine 4. COMMUNICATIONS The user interface for controlling the milling machine resides on a dedicated PC. Therefore there should be some means of communication between the software and the electronics hardware. A standard desktop personal computer consists of several communications ports. These include parallel port (LPT1), serial port (COM), PS/2 ports and Universal Serial Bus (USB) ports. Serial port communications has been used to with the electronics hardware. The Serial port or RS232 has several port settings that need to be set. The advantage of this obsolete technology is that it best suits the application we are designing, and the amount of data that needs to be sent to and from the milling machine. Figure 4.1 shows the dialog box that appears to the user when the user chooses Serial Port from the Setup Menu. On this dialogue box the user can choose the port settings. The reason for including this control is so that the application may work on different PCs. The default port setting is shown in figure 4.1. Figure 4.1 Serial Port Configuration dialog box The communications via RS232 was made possible using the system.IO.ports namespace, and the SerialPort class of Visual Basic 2008. The SerialPort class consisted of properties/attributes, methods and events which was used in the communication algorithm. The ReadExisting() method was used to read data from the PCs serial port receive buffer (Rx). The Write() method was used to send string data to the electronics of the CNC Milling Machine. The flowchart in figure 4.2 demonstrates how the communication to the milling machine is made when the user clicks ok on the dialog box in figure 4.1. Figure 4.2 Flowchart showing the communication algorithm followed. 5. TESTING AND DEBUGGING One problem faced during the development and testing of the GUI was run time errors or exceptions. Runtime errors or exceptions occur as a result of normal operating conditions [8]. For example errors when the GUI is trying to open a COM port which is being used by another program. The problem was overcome using structured error handling or the Try†¦Catch code block in Visual Basic. The GUI used message boxes to display appropriate messages to the users when an exception occurred and allowed the program to continue. The preview part of the GUI was tested by opening a text file containing 165 X, Y, Z points. These points resembled a circle in two dimensional (X, Y) planes. The result is depicted in Figure 5.1 which shows the tool path generated on the preview panel. Figure 5.1 Tool Path preview showing the preview of a circle Furthermore, the same file was used to mill a circle on softwood with the following settings: Feedrate 75mm/min Spindle Speed 2500RPM Cutting Tool Diameter 5mm The result is shown in Figure 5.2. The result shows that the Graphical User Interface made no errors while sequentially sending coordinates to the milling machine. Figure 5.2 Output of the CNC Milling Machine 6. CONCLUSION AND FUTURE WORK Based on the result in the previous section of this paper, it can be concluded that the GUI design was successful. The GUI was able to communicate with the electronics hardware of the CNC Milling Machine using RS232 serial link. The preview algorithm of the program also worked well. Finally the GUI was able to sequentially send (X, Y, and Z) coordinates representing cutter path in three dimensional space, to the CNC Milling machine. However, a number of tasks can be carried out in the future to improve the performance of the GUI and to enhance the output of the CNC Milling Machine. One such include the implementation of the industry standard G Codes which is based on ISO6983 data model, instead of X, Y, Z coordinate file. The G Code programming is a standardized way of controlling cutter motion. The CNC milling machine is capable of moving in steps as small as 1 tenth of a millimeter. Thus it is also recommended to improve the GUI so that it can cater for coordinates with one decimal point. The output of the CNC milling machine will improve drastically by having coordinates in mm to one decimal point. Another improvement that can be implemented on the GUI is using an abort button to cancel or abort the operations of the CNC Milling Machine. This is a standard safety feature which exists on most industrial machines including CNC machines.

Simultaneous Multithreading :: Threads Caches Hyper Threading Essays

Simultaneous Multithreading Simultaneous multithreading  ¡Ã‚ ª put simply, the shar-ing of the execution resources of a superscalar processor betweenmultiple execution threads  ¡Ã‚ ª has recently become widespread viaits introduction (under the name  ¡Ã‚ °Hyper-Threading ¡Ã‚ ±) into IntelPentium 4 processors. In this implementation, for reasons of ef-ficiency and economy of processor area, the sharing of processorresources between threads extends beyond the execution units; ofparticular concern is that the threads share access to the memorycaches.We demonstrate that this shared access to memory caches pro-vides not only an easily used high bandwidth covert channel be-tween threads, but also permits a malicious thread (operating, intheory, with limited privileges) to monitor the execution of anotherthread, allowing in many cases for theft of cryptographic keys.Finally, we provide some suggestions to processor designers, op-erating system vendors, and the authors of cryptographic software,of how this atta ck could be mitigated or eliminated entirely.1. IntroductionAs integrated circuit fabrication technologies have improved, provid-ing not only faster transistors but smaller transistors, processor design-ers have been met with two critical challenges. First, memory latencieshave increased dramatically in relative terms; and second, while it iseasy to spend extra transistors on building additional execution units,many programs have fairly limited instruction-level parallelism, whichlimits the extent to which additional execution resources can be uti-lized. Caches provide a partial solution to the first problem, whileout-of-order execution provides a partial solution to the second.In 1995, simultaneous multithreading was revived1in order to com-bat these two difficulties [12]. Where out-of-order execution allowsinstructions to be reordered (subject to maintaining architectural se-mantics) within a narrow window of perhaps a hundred instructions,Key words and phrases. Side channels, sim ultaneous multithreading, caching.1Simultaneous multithreading had existed since at least 1974 in theory [10], evenif it had not yet been shown to be practically feasible. -------------------------------------------------------------------------------- Page 2 simultaneous multithreading allows instructions to be reordered acrossthreads; that is, rather than having the operating system perform con-text switches between two threads, it can schedule both threads simul-taneously on the same processor, and instructions will be interleaved,dramatically increasing the utilization of existing execution resources.On the 2.8 GHz Intel Pentium 4 with Hyper-Threading processor,with which the remainder of this paper is concerned2, the two threadsbeing executed on each processor share more than merely the execu-tion units; of particular concern to us, they share access to the memorycaches [8]. Caches have already been demonstrated to be cryptograph-ically dangerous: Many implementations of AES [9] are subject to tim-ing attacks arising from the non-constancy of S-box lookup timings [1].

Isolation Form Love In The Film east Of Eden :: essays research papers

East of Eden by John Steinbeck is an optimistic film about a boy becoming a man and trying desperately to earn the love of his father and mother in the troubled times of the Great Depression. Cal, the main character is a troubled teen who lives with his entrepreneur father, and a brother who is following closely in his fathers steps. Cal’s mother left him and his brother to become a madam of a whorehouse. The struggle takes place between Cal and his father due to his fathers lack of compassion for his son. The conflict rises further when Cal tries to help his father repay a debt, his father further isolates his son and this turns to violent outbursts. Steinbeck focuses on Cal in order to suggest the theme that without love people become violent and mean. Steinbeck shows Cals isolation from love and its aggressive results when Cal angrily throws stones at his mothers house. When Cal first learns of his supposedly dead mothers existence he is outraged and goes to seek her. When he is not allowed to see her he violently throws stones and yells "Why can’t a kid see his own mother?" and "Why cant I see my mother". This is the first of several violent actions taken by Cal in an effort to be redeemed by his parents affections. His actions, although violent, are a symbol of his not being loved and the isolation he feels towards his family. In the scene where Cal tries to confer with his mother it is also learned that his mother does not want to have any contact with her children. Steinbeck shows Cals isolation from love, and its violent repercussions again when Cal reacts to his brothers lack of compassion for him with violence and destruction. In the scene when Cal is spying on his brother Aaron and his brothers girlfriend, he is outraged by the things his brother has to say and he decides to throw large blocks of his fathers ice out of the barn. This sole action shows how childlike Cal has remained due to his isolation from his families love. His unassuming father only says "that boy is out of control" not even acknowledging that there is a greater problem at hand, and even less does he understand the fact that it is partly his fault. Steinbecks theme of isolation form love is greatly illustrated because his father does not even take to scolding Cal, which shows no feelings what so ever.

Columbine High School Shooting Essay

Tuesday, April 20, 1999, was a turning point in the lives of many Columbine students and families. Eric Harris and Dylan Klebold, two former students at Columbine High School, went to school on that day for one purpose, to annihilate the school building as well as the student body. Although Eric and Dylan’s bombs did not detonate, they still succeeded in destroying the lives and families of the twelve students and the one teacher that died. The Columbine High School shooting occurred because of the premeditation of the shooters, the event of the school, and the results of the shooting. Eric and Dylan were just like most kids now a days entering high school. They came not knowing what to expect and soon realized no one even cared that they were there. They were bullied and picked on all the time. Eric and Dylan started a club called the Trench Coat Mafia which was known for its violent and vulgar language. Sometimes they would walk around school wearing trench coats to make the m seem stronger and to â€Å"protect† themselves in a way. Entering tenth grade was sort of the same for them, but it seemed to get worse quick. They started to participate in drinking, smoking, and petty crimes to make them more popular. The only people they got popular with were the police because they were constantly arrested for breaking into cars, homes, and stealing from stores. Eric over the course of all this developed serious anger problems and began taking Zoloft, a depressant, to make it better, but he started abusing the drugs and selling them for money. They made videotapes in Dylan’s basement showing them making pipe bombs and other explosives and talking about killing sprees. When they finally decided that they were going to do a killing spree in Columbine, they made more videos apologizing to their parents and other people and showing their ammunition. On Tuesday, April 20, 1999, Eric and Dylan left their houses as if it were a normal day, but the night before they had packed their book bags and some duffle bags with guns, rifles, explosives, pipe bombs, and 7-8 actual bombs. It was a normal day until around 11:00 a.m., Eric and Dylan entered the cafeteria with two rifles in hand firing random s hots everywhere. People scrambled to get out of the cafeteria, some thinking it was a joke and others realizing it was real. When the cafeteria was empty, they set up two bombs at opposite ends of the cafeteria. When they did not detonate, they were mad. After this first mishap, they ran across the school campus looking  to shoot anyone in sight and then they reached the library. The library is where they kill 7 out of 13 people. They taunted and fired random shots to scare the students that scrambled under the tables trying to protect themselves. Some were successful and some were not. After the library they returned to the cafeteria and this is where they committed suicide with one of the pipe bombs. The result of the shooting brought a devastating feeling on all the families and thankfulness to the families of the students that were not harmed. â€Å"Eric and Dylan are responsible for what they did, but Columbine is responsible for creating Eric and Dylan†. The event of Columbine still haunts us today with some of the more recent school shootings such as Sandy Hook Elementary. We will always remember what happened that Tuesday and try to prevent this ring of school shootings that seems to keep growing larger and larger from occurring anymore. The Columbine High School shooting occurred because of the premeditation of the shooters, the event at the s chool, and the results of the shooting.

A Synopsis of Roman Family Life Essay

Glancing towards the past of the old Roman Republic and the Roman Empire we are more than often charmed by and idealized view of the Roman family life adhering to the principles of virtus, dignitas, auctorias, gloria, pietas, and gravitas.1 As Beryl Rawson would argue in her essay on Roman family, this view is limited to that of the patrician class and the plentiful literature surrounding it .2 Furthermore, this outlook does not adequately account for core features of any social study of family such as the process of socialization of children, the extent of their education, specific gender roles, family structure, relationship between members, inheritance, and also does not incorporate the description of a Roman family within the context of other social classes. In order to get an ample insight of Roman society all the aspects previously enumerated need to be analyzed.  The general Roman family structure, by common consensus, was believed to be a small nuclear unit, yet the term of familia used in the period could have been much larger. Thus, the family consisted of the wedded couple plus the household dependents such as their unmarried children, slaves, and in some case freedmen and foster-children according to the research of Jerome Carcopino in the Daily Life in Ancient Rome. 3 At the head of the household was the oldest surviving male ascendant whose authority was recognized legally over his descendants and lasted until his death, known as the paterfamilias. Furthermore, the term familia could refer to all persons and property under the control ( patria potestas) of the paterfamilias, but more than often it was referred to the nuclear families household 4. Based on wealth or social class the size of the nuclear family varied greatly. However, during the period of the Roman Republic and then the Roman Empire the average size of the nuclear family was relatively small, ranging from the conjugal couple and about two to three children according to Rawson. 5 Under the hegemony of the paterfamilias, women and grown children would have  a very inferior legal status. The head of the family having â€Å"power of life and death over his legitimate children, [†¦], and full rights over property, including anything they might acquire. Daughters were removed from the father’s power when he gave them in marriage into a control of a husband.† 6 The act of marriage was regarded in ancient Rome more as a financial and political alliance than as a romantic association, especially in the upper classes. In any social class the primary purpose for marriage was to produce children. Since the life expectancy was so low in ancient Rome women married very early, fathers usually began seeking husbands for their daughters when these reached an age between twelve and fourteen. The husband was usually older than the bride between mid to late twenties. 7 The two official types of marriages were: with manus and without manus. The marriage with manus was the typical upper-class wedding and tended to be a lavish affair which incorporated a religious rights ceremony in the presence of the pontefix maximus 8. The marriage without manus was largely a more plebian affair in which there were no religious rights and the father emancipated his daughter to the husband. The third form of marriage was called the usus where after a year of cohabitation between a man and a woman they were by law considered married. 9 In order for a manus union of a man and woman to be legitimate, there needed to be consent legally and morally. Both parties had to be willing and intend to marry, and both needed their fathers’ consent. One of the most important aspects of the practical and business-like arrangement of Roman marriage was the dowry. The dowry was a contribution made by the wife’s family to the husband to cover the expenses of the household. The dowry was also how Roman families maintained their social status relative to each other. It was important to ensure that upon the end of a marriage, the dowry was returned to either the wife or her family. This was done in order to improve her chances of remarriage as well as to maintain the family resources. In ancient Rome, the dowry became the husband’s full legal property. In actuality, however, the purpose of the dowry often affected the husband’s freedom to use the dowry. In the case the dowry was given to help in the mainte nance of the wife, or if a legal provision was made for the wife or her family to reclaim the dowry should the marriage dissolve, the husband was restricted as to how he could make use of the dowry. In the case of marriages without manus since the bride was emancipated she retained her  property rights although her property came under control of the husband while she was married. 10  As previously mentioned political status held a place of honor within Roman society. Nobility or the rank of patrician was not simply bestowed upon an individual. It was gradually built up or torn down by a family thus the importance of a nomen or family name. In this sense legitimate children belonged to their father’s family and bore his family name. Illegitimate children belonged to their mothers and bore her family name. There were also cases where the paterfamilias had no children or none of his children survived adulthood. In this instance the head of the household could compensate by adopting a son who would oversee the family after his death and thus he would have an heir. As far as inheritance is concerned, when the head of the family dies the patria potestas goes to the designated heir which in most cases he was a male form the line of the husband. The only case when women and men were equal in inheritance is if you have a brother and sister of approximately th e same age. If the mother dies her dowry and holdings go directly to the designated heir. The only situation when married women had priority of inheritance was the respect of patria potestas of her mother’s brother. 11 The custom of divorce was usually reserved for serious marital faults, such as adultery, and could be employed by a husband at any time. Since marriage was often used as a political tool in ancient Rome, especially in the upper classes, divorces were common when new political opportunities presented themselves. If the wife was not at fault for the ending of the marriage, then she was able to reclaim her dowry. If the wife committed adultery, husbands got to keep a portion of the dowry. 12 When regarding women roles in society and family during the transition period of 133-43 B.C.E. , they were completely dependent of man, not being able to speak in public or to sell property or buy it without the consent of the males of the family. Legally at this time and era they were treated with inferiority to men 13. Gradually the current was changing towards the late period of the Republic as we can notice in the letter of Cicero to his wife Terentia and her actions as well as in Hortensia’s Speech. 14 Furthermore in this period, a Roman wife was generally understood as her husband’s companion and helper. She was next to him at banquets and parties  and shared his authority over the children, slaves and the household. Roman wives were no longer expected to live secluded lives. They could freely receive visitors, leave the house, visit other households, or leave to go shopping to list some examples .15 . While the nature of Rome’s patriarchal society persisted throughout the Imperial period equality within the conjugal couple with the end of the Roman Republic. The Roman family was the mold in which the character of the Roman was formed, much as the polis formed the character of the Athenian. Every Roman looked with pride upon his family and the deeds of his ancestors; and it was regarded as a great calamity for the family worship to become extinct and so do we as historians need to carefully preserve its history and understand their society by analyzing every piece of its puzzle. WORKS CITED Bradley, Keith. Discovering the Roman Family: Studies in Roman Social History. New York: Oxford University Press, 1991. Carcopino, Jerome. Daily Life in Ancient Rome. London: The Folio Society, 2004. Crook, John. The Roman Family. The Family in Ancient Rome: New Perspectives. Edited by Beryl Rawson. Ithaca, New York : Cornell University Press, 1986. Hughes, Sarah, and Brady Hughes. Women in World History. Readings from Prehistory to 1500. Vol. 2. Armonk, New York: M.E. Sharpe, 1997. Rawson, Beryl. The Roman Family. The Family in Ancient Rome: New Perspectives. Edited by Beryl Rawson. Ithaca, New York : Cornell University Press, 1986.