Notes, summaries, assignments, exams, and problems for Computers

M1: Fundamental Graph Definitions

Walks, Paths, and Circuits

Walk

A Walk is a finite alternating sequence of vertices and edges, beginning and ending with vertices, such that each edge is incident with the vertices preceding and following it. No edge appears more than once in a walk, though a vertex may appear multiple times.

• Closed Walk: A walk that begins and ends at the same vertex.
• Open Walk: A walk that begins and ends at different vertices.

Path

A Path is an open walk in which no vertex appears more than once. The number of edges in a path is called the length of the path. A self-loop can be included in a walk but not in a path. The terminal vertices of a path are of degree 1, and the remaining intermediate vertices are of degree 2.

Circuit

A... Continue reading "Essential Definitions and Theorems in Graph Theory" »

10LayerModelSecurity,10Security policies and mandates.9,Oversight of end-to-end processes to ensure compliance with enterprise security policies. Audit trails for the threads.8Security roles and responsibilities. Standard security practices as they relate to activities and exchanges. Security Architecture. Personnel security requirements. 3.10. Management7Application service security (e.g., integrity of the service and application code) and content security (e.g., security labels). Security of user access to IT. Privilege management. 6Framework service security (e.g., integrity of the service and application code of the framework). Content security labeling service and label checking service. Software-based content encryption/decryption services... Continue reading "Layered Security Model and IT Infrastructure Best Practices" »

Module 9: Firebase Application

Realtime Database

A cloud-hosted database. Data is stored as JSON and synchronized in real-time to every connected client. Provides easy-to-use services for authentication (email/password, 3rd-party providers like Google/Facebook).

Cloud Firestore

A flexible and scalable database for mobile, web, and development. It offers synchronization, offline support, and ACID transactions.

Cloud Functions

...

Hosting

CSS/JavaScript

Cloud Storage

Provides robust, secure file uploads and downloads for Firebase apps.

Module 10: UML Diagrams

Structural Diagrams

• Class Diagram: Shows class hierarchy, fields/attributes, and relevant methods.

How to Read

• Visibility:
  • +: Public
  • -: Private
  • #: Protected (accessed only by child classes)
• Relationships:

Annotation Elements

Used to notate and clarify the information presented.

Annotate Ribbon

Buttons: Aligned, Linear, Angular, Radial, Diameter, Arc Length, Spot Elevation, Spot Coordinate, Spot Slope, Detail Line, Region, Component, Revision Cloud, Detail Group, Insulation, Text, Check Spelling, Find/Replace, Tag By Category, Tag All, Beam Annotations, Multi-Category, Material Tag, Area Tag, Room Tag, Space Tag, View Reference, Tread Number, Keynote, Duct Legend, Pipe Legend, Color Fill Legend, and Symbol.

Annotate Ribbon Tab

Panels: Dimension, Detail, Text, Tag, Color Fill, and Symbol.

Application Menu

File access and management tools are grouped in this menu. This menu is designated by the large ‘R’ in the top left corner of the Revit screen.... Continue reading "Revit Elements and Tools: A Comprehensive Dictionary" »

Advantages of E-Governance

• Improves delivery and efficiency of government services.
• Improved government interactions with business and industry.
• Citizen empowerment through access to information.
• More efficient government management

Features of PHP

• Simple: It is very simple and easy to use, as compared to other scripting languages.
• Interpreted: It is an interpreted language, i.e. there is no need for compilation.

Supported Datatypes in PHP

• String: A string is a sequence of characters. A string can be any text inside quotes. You can use single or double-quotes.
• Integer: An integer data type is a non-decimal number between -2,147,483,648 and 2,147,483,647.
• Float (floating point numbers): A float (floating-point number) is a number with a decimal point or

Network Protocols (नेटवर्क प्रोटोकॉल)

Frame Relay क्या है? (What is Frame Relay in Hindi)

Frame Relay एक तेज गति का packet switching प्रोटोकॉल है जिसका प्रयोग Wide Area Networks (WANs) में किया जाता है। इसके अलावा, यह दो या दो से अधिक Local Area Networks (LANs) के बीच data को transfer करता है।

Frame Relay एक packet switched टेक्नोलॉजी है। इसे Local Area Networks के बीच कम खर्च में data transfer करने के लिए design किया गया था। साथ ही,... Continue reading "Frame Relay क्या है? फायदे और नुकसान (हिंदी में पूरी जानकारी)" »

Acid Rain: Concurrency-Related Attacks in Database-Backed Web Applications

Motivation:

• 12 popular self-hosted e-commerce applications (deployed over 2M websites, representing over 50% of all e-commerce websites)
• 22 critical ACIDRain attacks identified and verified
• Flexcoin -> Bankrupted

Problem Definition:

An application is vulnerable if:

• Anomalies Possible: Under concurrent API access, the application may exhibit behaviors (i.e., anomalies) that could not have arisen under serial execution.
• Sensitive Invariants: The anomalies arising from concurrent access lead to violations of application invariants.

Solution:

• Execute API calls against a live application and database to generate a (possibly sequential) trace of database activity.
• Analyze the trace

Understanding Computer Fundamentals

Output Devices

Plotter

A plotter is a specialized output device that generates images on paper, similar to a printer but with a distinct approach. Plotters excel at producing large-scale drawings or images, such as construction plans or blueprints. They can be connected to the same port typically used by a printer.

Tab Stops

Tab stops simplify document formatting. By default, they are set at 0.5-inch intervals from the left margin, allowing for easy creation of elements like tables of contents or indexes without manual adjustments.

Formatting and Data Visualization

Importance of Pie Charts

Pie charts effectively illustrate relative proportions or contributions to a whole using a single data series. Their effectiveness... Continue reading "Understanding Computer Fundamentals: Output Devices, Formatting, and Software Features" »

Core Graphic Design Concepts and Terminology

Vector Graphics and File Types

• Vector allows for resizing without loss in quality.
• Vector graphics are smaller in file size.

• PNG file type (Portable Network Graphics).
• SVG (Scalable Vector Graphics).

Digital Asset Sourcing

• He found the images online, but they were in the public domain.
• The team member created the images himself.

The whole is greater than the sum of the parts.

Typography and Text Handling

• Kerning: The spacing between specific pairs of characters.
• Leading: The distance between each line of text.

Font Classifications

• Script
• Decorative
• Serif
• Sans Serif

Text Overflow

Even though it's not visible, the excess text is still in the bounding area, and a small plus (+) symbol is displayed at the bottom of the... Continue reading "Essential Terminology for Graphic Design, Printing, and Web Projects" »

SkinnerDB: Regret-Bounded Query Evaluation via Reinforcement Learning

INTRODUCTION AND PROBLEM DEFINITION:

The work is on query optimization, more specifically: SkinnerDB focuses on finding the optimal Join Order. Because it has the most impact in practice.

SkinnerDB aims to get expected near optimal results without needing any a-priori information. It does not make strong assumptions either.

CONTRIBUTIONS:

• Introduced a new quality criterion for query evaluation strategies that compares expected and optimal execution cost.
• Proposed several adaptive execution strategies based on reinforcement learning.
• Formally proved correctness and regret bounds for those execution strategies.
• Experimental comparisations of those strategies, implemented in SkinnerDB,