The Hertzsprung-Russell Diagram or‚ the H-R Diagram for short‚ is a graph which plots stars according to their temperature and absolute magnitude. This graph reveals a pattern‚ which in fact is quite interesting. The H-R Diagram is named for the two astronomers‚ Ejnar Hertzsprung and Henry Russell‚ who discovered this pattern of stars. These two astronomers independently discovered that comparing magnitudes and spectral class (color) of stars yielded a lot of information about them. <br><br>One key
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Entity-Relationship Diagrams (ERD) Data models are tools used in analysis to describe the data requirements and assumptions in the system from a top-down perspective. They also set the stage for the design of databases later on in the SDLC. There are three basic elements in ER models: Entities are the "things" about which we seek information. Attributes are the data we collect about the entities. Relationships provide the structure needed to draw information from multiple entities. Generally
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DFD Yourdon Recently reviewed In the late 1970s data-flow diagrams (DFDs) were introduced and popularized for structured analysis and design (Gane and Sarson 1979). DFDs show the flow of data from external entities into the system‚ showed how the data moved from one process to another‚ as well as its logical storage. Figure 1 presents an example of a DFD using the Gane and Sarson notation. There are only four symbols: Squares representing external entities‚ which are sources or destinations
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Before starting this homework assignment‚ please review the AIB simulation in this week’s Lecture. This simulation will provide you with an understanding of how to create a network diagram‚ and how to do a forward and backward pass to determine the ES‚ LS‚ EF‚ LF and slack (float). You will also learn how to determine the duration of the project‚ and the critical path. In this homework assignment‚ you will be working through four Activity In Box (AIB) problems. Using the activity‚ duration‚ and
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The Iron-Carbon Diagram There are two iron-carbon equilibrium diagrams: - stable iron-graphite Fe-Gr - metastable iron-cementite Fe-Fe3C The stable condition usually takes a very long time to develop. The metastable diagram is of more interest. Fe3C iron carbide called cementite because it is hard. Following phases exist on Fe-Fe3C diagram: - liquid solution of iron and carbon (L) - ferrite ( ) – an interstitial solid solution of carbon in Fe (bcc). At room temperature ferrite is ductile but
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Using Data Flow Diagrams Data flow diagram is used by system analyst to put together a graphical representation of data processes throughout the organization. It depicts the broadest possible overview of system inputs‚ processes‚ and outputs. A series of layered data flow diagrams may be used to represent and analyze detailed procedures in the larger system. By using combinations of only four symbols‚ the system analyst can create a pictorial depiction of processes that will eventually provide
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Figure 1.0: Entity Relationship Diagram of Generic Academic Performance Monitoring System Figure 2.0: Context Diagram of Generic Academic Performance Monitoring System The figure 2.0 represents the two (2) users of the Generic Academic Performance Monitoring System namely the Administrator and the Professor. The Administrator entity shows the capability to access the system; manage account by modifying account’s profile; managing member’s account such as creating new user profile and updating
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Circular Flow Diagrams Introduction Money flows into and out of the economy. The circular flow diagram explains how money moves through the economic system involving households‚ businesses‚ the government‚ and foreign agents (Editorial Board‚ 2011). Circular flow diagrams are visual models that show firms who employ workers‚ the workers then spend on goods produced by firms‚ and the money is then used to compensate the worker and buy raw materials to make the goods and the circle continues.
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Food Web Diagram Sci/230 November‚ 2013 Desert Biome Food Web Diagram Food Web Diagram An ecosystem can be defined as a more or less self-contained function unit in ecology consisting of all abiotic and biotic
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Week 1-Discussion 1-Circular Flow Diagram To first explain how the circular flow diagram relates to the current economic situation‚ one must realize that the two‚ three‚ and four sector models no longer apply to the United States any more. Only the five sector model currently applies. The five sector model of the circular flow of income is a more realistic representation of the economy and has a more definitive look as to what and how economics really is in the world. In the more simplistic two
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