This document discusses static code analysis and challenges in analyzing PHP code. It describes analyzing if-statements, including estimating execution costs, handling interconnected conditions, and detecting duplicate expressions. It also covers analyzing exception handling workflows. The document provides examples of patterns found in if-statement analysis and discusses representing code constructs as graphs to solve the "shortest path problem" to estimate costs. It presents a formula for estimating the cost of if-else constructions and examples of hooking analysis code into an IDE.
Développer un moteur d'exécution symbolique en partant de rienJUG Lausanne
Session du 10 Janvier 2018
En chaque développeur a sommeillé un jour ce rêve d'écrire son propre compilateur pour un language de domaine ou voir même pour créer un nouveau language de programmation. Or le développement d'un analyseur de code ressemble étrangement au développement du front-end d'un compilateur. Durant cette session, Freddy présentera les différentes étapes du développement d'un analyseur de code jusqu'à la capacité à exécuter symboliquement tous les chemins d'exécutions. Ce concept avancé d'interprétation abstraite est un pré-requis à la détection des bugs et vulnérabilités les plus profonds dans tous les languages.
Quizz en ligne
20 minutes pour jouer ensemble et mettre à l'épreuve nos connaissances des principales failles de sécurité applicatives et notre capacité les détecter des bugs dans du code Java et JavaScript. Speaker
Freddy est le créateur de la plateforme SonarQube et est co-fondateur de SonarSource. Après de nombreuses années de développement en Java, il joue désormais le role de Product Manager pour les analyseurs de code SonarSource.
Développer un moteur d'exécution symbolique en partant de rienJUG Lausanne
Session du 10 Janvier 2018
En chaque développeur a sommeillé un jour ce rêve d'écrire son propre compilateur pour un language de domaine ou voir même pour créer un nouveau language de programmation. Or le développement d'un analyseur de code ressemble étrangement au développement du front-end d'un compilateur. Durant cette session, Freddy présentera les différentes étapes du développement d'un analyseur de code jusqu'à la capacité à exécuter symboliquement tous les chemins d'exécutions. Ce concept avancé d'interprétation abstraite est un pré-requis à la détection des bugs et vulnérabilités les plus profonds dans tous les languages.
Quizz en ligne
20 minutes pour jouer ensemble et mettre à l'épreuve nos connaissances des principales failles de sécurité applicatives et notre capacité les détecter des bugs dans du code Java et JavaScript. Speaker
Freddy est le créateur de la plateforme SonarQube et est co-fondateur de SonarSource. Après de nombreuses années de développement en Java, il joue désormais le role de Product Manager pour les analyseurs de code SonarSource.
Automatic Variables
extern variables
static variables
register variables
Examples of above listed variables.
Summary of storage place, Initial value, scope and life of variables.
A- Storage classes in C
B- Automatic variables
C- External variables or Global variable
D- Static variables
E- Register variables
Problem when extern is not used
Example Using extern in same file
Talk I gave to The Coding Machine about PHP 8. Overview of the RFC process and which QoL, features and notable BC breaks before finishing on some performance improvements.
For many years Object Oriented and Functional Programming have been considered diametrically opposite programming paradigms, with opposite communities.
Here we take the opposite point of view: they're two puppies from the same litter. Going through the well known SOLID Principles for good Object Oriented design and describing how some use of functional principles help improve the code.
Automatic Variables
extern variables
static variables
register variables
Examples of above listed variables.
Summary of storage place, Initial value, scope and life of variables.
A- Storage classes in C
B- Automatic variables
C- External variables or Global variable
D- Static variables
E- Register variables
Problem when extern is not used
Example Using extern in same file
Talk I gave to The Coding Machine about PHP 8. Overview of the RFC process and which QoL, features and notable BC breaks before finishing on some performance improvements.
For many years Object Oriented and Functional Programming have been considered diametrically opposite programming paradigms, with opposite communities.
Here we take the opposite point of view: they're two puppies from the same litter. Going through the well known SOLID Principles for good Object Oriented design and describing how some use of functional principles help improve the code.
Arabic 3: Basics on the nominal sentence Mohamed ZAIM
¨ Arabic 3: Basics on the nominal sentence ¨ is the first step to live a sentence in Arabic. You will find all necessary details that help understanding well the function of each part of it and so knowing deep the secret meaning and grammar that such lovely sentence carries. The slides are available also beside others on my blog:
www.alif-zaim.blogspot.com > ¨Grammar Slideshare¨ section cross column on right. Enjoy !
Applying Compiler Techniques to Iterate At Blazing SpeedPascal-Louis Perez
In this session, we will present real life applications of compiler techniques helping kaChing achieve ultra confidence and power its incredible 5 minutes commit-to-production cycle [1]. We'll talk about idempotency analysis [2], dependency detection, on the fly optimisations, automatic memoization [3], type unification [4] and more! This talk is not suitable for the faint-hearted... If you want to dive deep, learn about advanced JVM topics, devoure bytecode and see first hand applications of theoretical computer science, join us.
[1] http://eng.kaching.com/2010/05/deployment-infrastructure-for.html
[2] http://en.wikipedia.org/wiki/Idempotence
[3] http://en.wikipedia.org/wiki/Memoization
[4] http://eng.kaching.com/2009/10/unifying-type-parameters-in-java.html
PHP 8.0 is expected to be released by the end of the year, so it’s time to take a first look at the next major version of PHP. Attributes, union types, and a just-in-time compiler are likely the flagship features of this release, but there are many more improvements to be excited about. As PHP 8.0 is a major version, this release also includes backwards-incompatible changes, many of which are centered around stricter error handling and more type safety.
This talk will discuss new features already implemented in PHP 8, backwards-compatibility breaks to watch out for, as well as some features that are still under discussion.
PHP 8.0 is expected to be released by the end of the year, so it’s time to take a first look at the next major version of PHP. Attributes, union types, and a just-in-time compiler are likely the flagship features of this release, but there are many more improvements to be excited about. As PHP 8.0 is a major version, this release also includes backwards-incompatible changes, many of which are centered around stricter error handling and more type safety.
Presentation from phpfwdays 2020.
Go 1.10 Release Party, featuring what's new in Go 1.10 and a few deep dives into how Go works.
Presented at the PDX Go Meetup on April 24th, 2018.
https://www.meetup.com/PDX-Go/events/248938586/
This talk introduces some code metrics concepts with easy examples, and how to obtain them in PHP using tools like phploc, phpdepend, phpmetrics, etc. It follows with a discussion on which metrics are relevant, how we are already using them in some projects and how we should evaluate them in our department.
Big Data Day LA 2015 - Compiling DSLs for Diverse Execution Environments by Z...Data Con LA
Data transformation has traditionally required expertise in specialized data platforms and typically been restricted to the domain of IT. A domain specific language (DSL) separates the user’s intent from a specific implementation, while maintaining expressivity. A user interface can be used to produce these expressions, in the form of suggestions, without requiring the user to manually write code. This higher level interaction, aided by transformation previews and suggestion ranking allows domain experts such as data scientists and business analysts to wrangle data while leveraging the optimal processing framework for the data at hand.
Code is not text! How graph technologies can help us to understand our code b...Andreas Dewes
Today, we almost exclusively think of code in software projects as a collection of text files. The tools that we use (version control systems, IDEs, code analyzers) also use text as the primary storage format for code. In fact, the belief that “code is text” is so deeply ingrained in our heads that we never question its validity or even become aware of the fact that there are other ways to look at code.
In my talk I will explain why treating code as text is a very bad idea which actively holds back our understanding and creates a range of problems in large software projects. I will then show how we can overcome (some of) these problems by treating and storing code as data, and more specifically as a graph. I will show specific examples of how we can use this approach to improve our understanding of large code bases, increase code quality and automate certain aspects of software development.
Finally, I will outline my personal vision of the future of programming, which is a future where we no longer primarily interact with code bases using simple text editors. I will also give some ideas on how we might get to that future.
One of the biggest problems of software projects is that, while the practice of software development is commonly thought of as engineering, it is inherently a creative discipline; hence, many things about it are hard to measure. While simple yardsticks like test coverage and cyclomatic complexity are important for code quality, what other metrics can we apply to answer questions about our code? What coding conventions or development practices can we implement to make our code easier to measure? We'll take a tour through some processes and tools you can implement to begin improving code quality in your team or organization, and see what a difference it makes to long-term project maintainability. More importantly, we'll look at how we can move beyond today's tools to answer higher-level questions of code quality. Can 'good code' be quantified?
One of the biggest problems of software projects is that, while the practice of software development is commonly thought of as engineering, it is inherently a creative discipline; hence, many things about it are hard to measure. While simple yardsticks like test coverage and cyclomatic complexity are important for code quality, what other metrics can we apply to answer questions about our code? What coding conventions or development practices can we implement to make our code easier to measure? We'll take a tour through some processes and tools you can implement to begin improving code quality in your team or organization, and see what a difference it makes to long-term project maintainability. More importantly, we'll look at how we can move beyond today's tools to answer higher-level questions of code quality. Can 'good code' be quantified?
Twins: Object Oriented Programming and Functional ProgrammingRichardWarburton
Object-Oriented Programming has well established design principles, such as SOLID. For many developers architecture and functional programming are at odds with each other: they don’t know how their existing tricks of the trade convert into functional design. This problem becomes worse as hybrid languages such as Java 8 or Scala become common. We’ll talk about how functional programming helps you implement the SOLID principles, and how a functional mindset can actually help you achieve cleaner and simpler OO design.
Practical tips for dealing with projects involving legacy code. Covers investigating past projects, static analysis of existing code, and methods for changing legacy code.
Presented at PHP Benelux '10
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Water scarcity is the lack of fresh water resources to meet the standard water demand. There are two type of water scarcity. One is physical. The other is economic water scarcity.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Explore the innovative world of trenchless pipe repair with our comprehensive guide, "The Benefits and Techniques of Trenchless Pipe Repair." This document delves into the modern methods of repairing underground pipes without the need for extensive excavation, highlighting the numerous advantages and the latest techniques used in the industry.
Learn about the cost savings, reduced environmental impact, and minimal disruption associated with trenchless technology. Discover detailed explanations of popular techniques such as pipe bursting, cured-in-place pipe (CIPP) lining, and directional drilling. Understand how these methods can be applied to various types of infrastructure, from residential plumbing to large-scale municipal systems.
Ideal for homeowners, contractors, engineers, and anyone interested in modern plumbing solutions, this guide provides valuable insights into why trenchless pipe repair is becoming the preferred choice for pipe rehabilitation. Stay informed about the latest advancements and best practices in the field.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
4. Challenges we met
● If-statements analysis:
○ Execution costs estimation;
○ Interconnected conditions; if (is_array($a) && $a[0] > 0) ;
○ Variadic constructions, booleans, identical sub-expressions detection and more;
● exceptions handling workflow analysis:
○ Simulation of the workflow for running analysis;
○ PhpDoc parsing: PHP is not supporting “throws” declarations;
○ Nested catch and finally has implementation issues in older PHP versions;
● analysis performance:
○ Concurrency (inspections are running in several independent threads);
○ GC: memory optimization (VisualVM, data structures);
○ Avoid low-performing analysis, stop as early as possible;
5. Challenges we met
● If-statements analysis:
○ Execution costs estimation;
○ Interconnected conditions;
○ Variadic constructions, booleans, identical sub-expressions detection and more;
6. If-statements analysis: patterns
● Execution costs: if ($var->method($a) && $b > 0) ;
● Identical operands: if ($a !== $a) ;
● Ambiguous type checks: if ($a instanceof Date || $a instanceof DateInterface) ;
● If ($a instanceof DateInterface && null !== $a) ;
● Variadic constructions: if (isset($a) && isset($b)) ; => if (isset($a, $b)) ;
● Hardcoded booleans: if ($a > 0 || true) ;
● Confusing conditions: if ($a > 0 || $a <= 0 && $a > $minValue) ;
● Duplicated expressions in elseif and nested ifs:
● If (is_array($a) || is_string($a)) {
● If (is_array($a) && count($a) > 0) ;
● }
7. Execution costs estimation: idea
The challenge has a name: “Shortest path problem” from Graphs theory (Discrete
mathematics).
Applying the problem e.g. to “if ($var->method($a) && $a > 0) ;” we have 2 paths:
● $var->method($a)
○ Method lookup ;
○ Calls stack: push and pop ;
○ Complex operation, therefore high execution costs ;
● $a > 0
○ Primitive operation, therefore low execution costs ;
8. Execution costs estimation: example
Let’s take more common case: if-else construct.
If (<conditions>) {
<operation 1>;
} else {
<operation 2>;
}
Formula for if-else construction cost estimation will be*:
C(<if-else>) = C(<conditions>) + max(C(<operation 1>), C(<operation 2>))
* The theory of parsing, translation, and compiling
9. Execution costs estimation: C() function
This is most important part: which weight to assign to different constructs?
For this you need know your compiler/interpreter internals and language
capabilities.
Example weights specific for PHP:
● Binary/Unary operations: 0 ; (primitive operations)
● Array access: +1 (hash-maps based arrays implementation) ;
● Method/function reference: +5 (call stack invocation) ;
● Lambdas: +10 (no JIT compiler, dynamically allocated) ;
● etc.
10. Code samples: hooking into IDE
public class NotOptimalIfConditionsInspection extends BasePhpInspection {
@Override
public PsiElementVisitor buildVisitor(@NotNull final ProblemsHolder holder, boolean isOnTheFly) {
return new BasePhpElementVisitor() {
public void visitPhpIf(If ifStatement) {
/* we are visiting a branch of AST-tree here, analyze it */
}
/* other visitors here */
};
}
}