modeling

问题 PROBLEM I have a fairly large Hydro-Pneumatic system model composed of roughly 20-25 different subsystems. Each of the subsystem is then composed of digital logic, edge delay blocks, and gateway to external output ports (real-world outputs). Additionally some of the small building blocks are legacy C code imported as S-functions in order to maximise cost-benefit ratio. Each of the subsytem model has been designed in SIMULINK with the use of basic blockset i.e. no add-on commercial blocksets

问题 I'm trying to model a pulse waveform in my application and I need a way to keep track of the pulses so that I can repeat their sequence. From the figure shown below, what I'd like to do is simulate the first three pulses (pulse 1-3), then simulate pulse 4 immediately after pulse 3, and simulate pulse 5 immediately after 4. Then repeat the whole sequence N times. As shown in the diagram, I have the interval in seconds, the start time of the first pulse in seconds, and the duration of each

问题 I'm developing an application with Google App Engine and stumbled across the following scenario, which can perhaps be described as "MVP-lite". When modeling many-to-many relationships, the standard property to use is the ListProperty. Most likely, your list is comprised of the foreign keys of another model. However, in most practical applications, you'll usually want at least one more detail when you get a list of keys - the object's name - so you can construct a nice hyperlink to that object

问题 Sometimes more than one artist will be on a song. For example, Jay-z's new song "A Star is Born" features the artist Cole, and thus would be listed as "Jay-z (featuring Cole) - A Star is Born" in a catalog. My question is how to model this in my database. Right now it's pretty simple: every song belongs_to :artist and every artist has_many :songs . I want to change this so that songs have many artists, with one artist specified as "primary" -- i.e., if A, B, and C are all associated with a

问题 Suppose I have Student and Teacher in a many to many relationship. If I just want to find out all the teachers for a given student or vice versa I generally model it by using embedded Object Ids. For example if teacher has a property studentIds which is an array of student Object Ids then that is enough information to do all the queries you need. However suppose that a student can give a teacher a rating. How should this rating fit into the model? At the moment I do the following: Inside

问题 Very simple scenario N users, each user can have 0 .. N - 1 friends (who are also users) How can I model this in Java for AppEngine data store Scenario to consider user x and user y become friends (so both need update their own status, in a transaction 回答1: We've modeled user relations as a simple UserRelation entity: class UserRelation { User _from; User _to; RelationState _state; } Where RelationState is an enum, describing states (normally, there is more than friendship) enum RelationState

问题 Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Stack Overflow. Closed 6 years ago . Is this a legit tool or is it a crutch that I will eventually grow out of needing? Update : By order of operations, I mean: launch app read prefs calculate value from prefs write prefs to file... Right now, I draw diagrams at the method level as well as the app level when I'm having trouble visualizing the

问题 I have a gls model in which I assign a formula (from another object) to the model: equation <- as.formula(aic.obj[row,'model']) > equation temp.avg ~ I(year - 1950) mod1 <- gls(equation, data = dat) > mod1 Generalized least squares fit by maximum likelihood Model: equation Data: dat Log-likelihood: -2109.276 However I do not want the "Model" to be "equation" but rather the quation itself! How do I do this?? 回答1: This is pretty standard, even lm would do this. One approach: hijack the print

问题 sometimes a red triangle appears over some (not all!) of my requirement artifacts that I have constructed before starting more detailed UML work and development. I have no idea what causes it or what it is meant to express. What's more, I cannot get rid of it. ;) As far as I know this has nothing to do with the UML or SysML specification - or does it? Can anyone explain? Thanks :) 回答1: It has nothing to do with UML or SySML. What is says is that someone bookmarked the element. You may have

问题 My specific problem is actually not about the general translation of an OO interface to Haskell. This is just the best title I could come up with. Yet, I'm sure that my problem originates from a still poor understanding of modeling code with Haskell and a mindset still located in the land of OO paradigms (still a haskell beginner, you see). I'm writing a Mastermind (variation) simulation to test the fitness of several Mastermind strategies. As a matter of fact, I already did that in Java and