The Therac 25 A case study in safety failure • Radiation therapy machine • “The most serious computer-related accidents to date” • People were killed • Reference: Nancy Leveson and Clark Turner‚ “The Investigation of the Therac-25 Accidents”‚ Computer‚ 26‚ 7 (July 1993) pp 18-41. Therac 25 Background • Medical linear accelerator developed by Atomic Energy of Canada‚ Ltd. in mid-1970s • Delivers 25 MeV photons or electrons of various energies • Controlled by PDP-11 minicomputer • Software
Premium Therac-25
CASE 5 Why Did Global Food Prices Rise? Case Summary For the past 25 years‚ food prices have been declining due to increased productivity and output from the farm sector worldwide. In 2007 however‚ this changed. There are two main explanations to this. The first is an increased demand for food in rapidly developing nations such as China and India. Meat in particular has contributed to the rising prices as farmers have to feed their animals an extensive amount of grain in order to keep up with
Premium Biodiesel European Union Agriculture
An Investigation of the Therac-25 Accidents -- Part III Nancy Leveson‚ University of Washington Clark S. Turner‚ University of California‚ Irvine Reprinted with permission‚ IEEE Computer‚ Vol. 26‚ No. 7‚ July 1993‚ pp. 18-41. Recall that the Tyler error occurred when the operator made an entry indicating the mode/energy‚ went to the command line‚ then moved the cursor up to change the mode/energy‚ and returned to the command line all within 8 seconds. Since the magnet setting takes about 8 seconds
Premium Software engineering Therac-25 Software testing
Some of the 25 statements listed below are from the official website of the company‚ while others were found from second hand sources; some are official mission statements‚ others are parts taken from company overviews or the introduction to a site’s About page‚ as not all companies or sites define their mission clearly. 1. IBM: “At IBM‚ we strive to lead in the invention‚ development and manufacture of the industry’s most advanced information technologies‚ including computer systems‚ software
Premium Wikipedia Social network service Social network
Chapter 25-Urinary System Aldosterone is a hormone that causes the renal tubules to reclaim sodium ions from the filtrate. =TRUE The kidneys are stimulated to produce renin ________. =by a decrease in the blood pressure An important characteristic of urine is its specific gravity or density‚ which is ________. =1.001-1.035 Which of the following is the functional unit of the kidney? =Nephron In which part of the kidney is reabsorption (1) dependent upon the body’s needs at
Free Kidney Nephron
Egon Zehnder International IB 207 10/11/2010 Dr. Neelankavil J. Amit Khoje Strategic Review at Egon Zehnder International The Problem Egon Zehnder International (EZI) has steadily developed its reputation over 36 years. In these years‚ the firm carried certain values which Zehnder – the founder of the firm – thought were the building blocks of the firm and should never be compromised. But as the search industry has undergone dramatic changes in recent years‚ and also internally the
Premium Patient Health care United States
• The citizenship status of the criminals in this case are that they are citizens of The Federal Republic of Nigeria. The criminals do not have dual citizenship status‚ so they are not United States citizens and fall outside of the jurisdiction of the U.S. This will require The United States to bring the case to the International Criminal Court‚ where the Prosecutor will investigate and decide if charges will be brought. This limits and slows down the ability of The United States to apprehend
Premium Crime Police Law
FACT: “Imperial Pacific International (CNMI) LLC earned over $1 billion in gross gaming revenue from January to July 2017‚ according to documents obtained by Saipan Tribune” (Casino‚ 2017). The Imperial Pacific International Holdings Limited develops and operates destination casinos. Imperial Pacific Holdings is headquartered in Hong Kong. This business began as a natural foods company‚ but transitioned to gaming when it purchased Macau-based junket venture Hengsheng in 2013 for HK$400 million ($51
Premium Northern Mariana Islands Saipan
Issues 1. Explain why an individual investor might want to invest in an international growth fund? 2. Describe the risk associated with making an investment in an international growth fund. Identify the risks that would be common to domestic an international funds‚ and those risk that would be unique to an international fund. 3. Discuss how the fact that foreign companies are not subject to the same accounting‚ auditing‚ and financial reporting standards and practices as U.S. companies poses
Premium Investment Finance Risk
In Journal 25‚ where I will discover course improvements I need to make or already have made to correct my results and experience. A. Describe an important course correction you have made in the past. I was a 17 years old senior in high school. Not taking university application seriously. True that I graduate high school with high grade point average. However‚ I missed the university application deadline. I’ve should have known that everything has a deadline nothing going to wait. So I ended up
Premium High school College Education