MSDN Magazine - January 2009 - (Page 45)

Figure 7 PERIL Likelihood for Five B=Categories Very High High Medium Low Very Low l1 = (1 + 1/2 + 1/3 + 1/4 + 1/5) / 5 = 0.45667 l2 = (0 + 1/2 + 1/3 + 1/4 + 1/5) / 5 = 0.25667 l3 = (0 + 0 + 1/3 + 1/4 + 1/5) / 5 = 0.15667 l4 = (0 + 0 + 0 + 1/4 + 1/5) / 5 = 0.09000 l5 = (0 + 0 + 0 + 0 + 1/5) / 5 = 0.04000 Figure 8 PERIL Impact for Four Categories Very High High Low Very Low i1 = (1 + 1/2 + 1/3 + 1/4) / 4 = 0.52083 i2 = (0 + 1/2 + 1/3 + 1/4) / 4 = 0.27083 i3 = (0 + 0 + 1/3 + 1/4) / 4 = 0.14583 i4 = (0 + 0 + 0 + 1/4) / 4 = 0.06250 What are you looking for in a PDF solution? Amyuni PDF Suite combines our high-performance PDF Converter and PDF Creator products: Figure 9 Example PERIL Exposure Risk A B C D Likelihood Very Low Medium Very High High Impact High Very Low Very High Low PERIL Exposure 0.01083 0.00979 0.23785 0.03743 PDF Converter I Integrate PDF conversion capabilities into any application using a few lines of code I Work with a PDF converter designed to perform in multi- threaded and 64-bit Windows environments I Convert documents into PDF in a fraction of the time Let me show you an example. Suppose you have identified four risks: A, B, C, and D. Now suppose you decide that trying to assign meaningful numeric values to each risk’s probability and loss is just not feasible. Additionally, you decide that in your particular environment it makes sense to categorize risk likelihood into five categories: Very Low, Low, Medium, High, and Very High. Next, you determine that you will categorize loss/impact on a four-point scale: Very Low, Low, High, and Very High. The PERIL technique maps categorical data onto a quantitative scale using a simple mathematical construct called rank order centroids. The mapping technique is best explained by example. For the five-category likelihood scale my five rank order centroid mappings are shown in Figure 7. Similarly, my four-category impact mappings are computed, as shown in Figure 8. Now I can combine each risk’s likelihood and impact centroid value to compute the risk’s exposure by multiplying. For example, look at Figure 9. Here, Risk D has High likelihood, which maps to 0.25667, and Low impact, which maps to 0.14583, so the exposure is 0.25667 * 0.14583 = 0.03743. From this data I conclude the Risk C clearly has the highest exposure, and I would look at ways to prevent the risk from occurring and create a contingency plan if the risk event does occur. Instead of computing each risk’s exposure individually, I can construct a complete PERIL exposure lookup table for five likelihood levels and four impact levels, and then simply read PERIL exposure values from the table, as illustrated in Figure 10. The PERIL technique generalizes to any number of likelihood and impact categories. Rank order centroids map ranks (such as first, second, third) to numeric values (such as 0.61111, 0.27778, 0.11111). Notice that rank order centroid values are normalized in the sense that they sum to 1.0 (subject to rounding error). Expressed in sigma notation, if msdnmagazine.com used by other tools I Generate ISO-compliant documents using PDF/A and PDF/X formats I Develop custom plugins that enable page-by-page processing of PDF data PDF Creator I View, edit, annotate, and print PDF documents and forms I Include different types of form objects and annotation tools such as edit fields, check boxes, sticky notes, and highlighters I Create well structured, optimized, and accurate PDF documents I Embed standard or custom XMP metadata in PDFs to facilitate document exchange I Export PDF documents into a number of formats such as XPS, RTF, HTML, JPEG, TIFF, and Excel www.amyuni.com All trademarks are property of their respective owners. © 1999-2009 AMYUNI Technologies. All rights reserved. January 2009 45 http://www.amyuni.com http://www.amyuni.com http://www.msdnmagazine.com

Table of Contents Feed for the Digital Edition of MSDN Magazine - January 2009

Toolbox CLR Inside Out Basic Instincts Cutting Edge Test Run First Look� Geneva Framework Silverlight Windows Mobile Service Station Security Briefs Extreme ASP.NET Foundations .NET Matters { End Bracket }

MSDN Magazine - January 2009

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