I recently heard about a type of priority queue called a "pagoda" that allegedly has excellent runtime guarantees. In fact, some of the references I've found on it have suggested that it's one of the fastest priority queue implementations available. Surprisingly, though, I can't seem to find a single good resource on this data structure anywhere on Google or Bing.
Does anyone know of any good resources (analysis, source code, etc.) on this data structure?
Pagodas: pg 174 of the "Handbook of Algorithms and Data Structures" by G.H. Gonnet (published 1984). Contains psuedocode and analysis.
There is a more recent version of this book here.
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I'm developing an Android app that uses an ELM327 device for OBD-II communications, and I'd like to be able to get the status of the headlights. Specifically, I would like to know if the driver has turned them on or not, but it would also be moderately useful to be able to tell what lights are on (mains vs brights vs DRLs and so on) and whether or not any of the bulbs are out. I was under the impression that there were ways of figuring out whether the headlights were on over OBD-II, but I can't find anything to confirm that, and the API I'm using (the pires obd-java-api on Github) doesn't have anything in it either. Can I actually do any of this?
All the standardized OBD PIDs are within ISO 15031-5 standard. Some part of it can be found in Wikipedia and here as well. All the other PIDs are vehicle specific PIDs which you cannot generalized (or even find) them.
The PIDs that you are searching for might not be standard or supported by every vehicle.
While making good ontology is for sure big and mostly manual effort, it could be interesting to know if there are any techniques / tools, which automate making vendor-specific, intermediate ontologies for ETL process, given, say, rich-enough JSON examples combined with API documentation.
I am aware of Linked Data standards and techniques, but may be there is something in the form of library to make a draft RDFS+ ontology from API call responses?
For example, there are some libraries to guess JSON Schema (I have even written a primitive one myself), so the task does not seem to have problems in theory.
Please, do not consider this question as "software recommendation" one, because I doubt there is any software for this, but at least educated guess at direction I can take with this. I also believe, this is very important for semantic / linked data projects, and I wonder why I can't find any hints and need to ask for help from more experienced here.
Different kind of software offer different amount of configuration/customization. Routers are one of the most configurable software systems I know of. I want to know how routers handle configurations - how they alter the code flow based on the configuration?
One obvious way is to use if..else clauses provided by most of the language(let's assume we are using C)
So is there any other programming method(or paradigm?)
Data-driven programming paradigm may be viable one. Configuration can be thought of one of the input source and so can be used to alter the code flow.
What I need to know is, is there any papers and references that I can use to enrich my understanding. Not just routers any kind of software. If the question seems to vague, let me know I will add more details.
I don't know anything about configuration of routers, but your question states you are interested in configuration for any kind of software, so the following might be of interest to you.
I am the author of Config4*, which provides C++ and Java parsers for a particular configuration syntax. I suggest you do the following. Skim Chapters 2 and 3 of the "Config4* Getting Started Guide" (HTML, PDF) to get an overview of the configuration syntax and API. Then take your time reading the "Config4* Practical Usage Guide" (HTML, PDF), which discusses the "how to" for a variety of different ways to use configuration. Although the discussion in that manual makes use of the Config4* syntax and API, the principles could be used with another syntax, for example, XML. If you focus on the principles discussed in that manual, rather than the syntax, then I suspect you will start to develop some insight into how a router handles its configuration.
I've started using Raven for my last project. When my boss learned about it, he mentioned it's based on Access and he had very bad experience with multiple users and Access. Now I have to either switch or prove to him he is wrong.
No, it isn't. The confusion is because RavenDB can use ESENT for data storage and ESENT used to be called Jet Blue. It was called Jet Blue because it was originally developed to replace the Jet Red engine which was/is used in Access. The Wikipedia entry is quite accurate about the history and differences.
Laurion's answer is correct, but I also wanted to point out that in Raven you can swap out the ESENT storage engine for another that Oren developed called Munin.
From Ayende's blog post about Munin.
Raven.Munin is the actual implementation of a low level managed storage for RavenDB. I split it out of the RavenDB project because I intend to make use of it in additional projects.
At its core, Munin provides high performance transactional, non relational, data store written completely in managed code. The main point in writing it was to support the managed storage in RavenDB, but it is going to be used for Raven MQ as well, and probably a bunch of other stuff as well. I’ll post about Raven MQ in the future, so don’t bother asking about it.
Munin is a low level api, not something that you are likely to use directly. And it was explicitly modeled to give me an interface similar in capability to what Esent gives me, but in purely managed code.
We've been using SysV Message Queue for our distributed data processing system for over 15 years. For some reason, we want to replace it with newer Message Queue mechanism. Is there any suggestions?
Requirements:
Fast response, minimizing message queue system overhead
Multiple client language library support, mainly c, c# and java
Can do some HA configuration to prevent SPOF
Have logging ability to check who sends message and who receives message
I've found Apache ActiveMQ and RabbitMQ, but it seems RabbitMQ lacks of stable C client library support?
While I have not used it personally, the toolkit from 0MQ is quite impressive.
It seems to meet all of your criteria, although #4 you would have to implement yourself, but that seems straightforward.
My question back would be why you are moving away from SysV Message Queue? The "for some reason" is a disconcerting statement.
That said, there are many excellent messaging products out there, having a useful set of selection criteria is key.
I would suggest extending your requirements list a bit, then doing website bench-marking against that list. Take the top two or three only, and do some real-world project spikes (or a bake-off if you prefer the term) to give you some actual feedback on which to base your final decision.
Good Luck