Developers Club geek daily blog

Critical errors of design of industrial control system and programming of a PLC

1 year ago
Automated control systems for technology process (Industrial control system) on the industrial programmable logic controllers (PLC) on objects of upgrade are implemented into the industries. Again delivered equipment, already by default contains an ACS on a PLC. But quality of design of industrial control system and programming of a PLC sometimes does not correspond to logic and requirements to reliable protection of managed object. In this article I will tell about a typical error of design and programming of normal industrial equipment.

Read more »


Centrifugal compressor units. Protection against a surge

1 year ago
Compressor units in the industry are used in many technology operations. Compressed air is received different types of compressor units. From rotor type, to vortex turbomachines. Centrifugal K-250 compressor units have a wide circulation in the industry. But all types of compressors have a critical duty of work – a surge.


Read more »


Creation of business process in the BPEL language with use of the Serena Business Manager platform

1 year, 1 month ago
Having passed by search in Habrakhabr, it was succeeded to find not so a lot of information, devoted, it is necessary to tell, to not really widespread BPEL language (Business Process Execution Language). If to speak generally, then BPEL is the language based on the XML format which allows to describe logic of business processes through use of web services.


Implementations of the engines allowing to create processes with use of this language I know not so much. In particular, it is possible to mention Oracle BPEL Process Manager and a product about which the speech further – Serena Business Manager (SBM) will go. SBM allows to create quickly the web applications automating some process. An opportunity at the time of state change to call external web service is provided in a process model (workflow). And if it is necessary to implement some logic and one challenge insufficiently? Here also the procedure written in the BPEL language and performed by means of the same BPM platform is useful.

I will not dwell upon the language, it is possible to find enough information in a network on this subject, for example, here. I will describe implementation of a specific objective.

Read more »


Use of Google Analytics in games

1 year, 1 month ago
During development of the game SUPERVERSE we needed means for tracking of how players interact with game, and also receipts of data on "iron", a display resolution, operating system, etc. These data could be useful not only at a debugging stage, but also would help to study features of behavior of users in game.


Read more »


Evolution in a cloud: experience of service for work with social networks

1 year, 1 month ago

Read more »


Bizagi — system of modeling, development and execution of business process. The description with an example

1 year, 1 month ago
I wrote this article throughout article about BPM systems. And here I want to tell about the principles of work of BPMS on the example of specific system — Bizagi. I will try to explain how there is a process of modeling, development and execution of business process in this system on a practical example.

Bizagi: Model. Build. Run

Read more »


What is BPMS

1 year, 1 month ago
Today in domestic business the new type of the software for business process management, namely, BPMS systems gains popularity. And, naturally, their emergence raised many questions. Why they are necessary? How they work? In what their fundamental difference from other options of automation of business?

When I for the first time faced BPMS, I also had all listed above questions. I far understood not at once why the new tool why it is impossible to implement all business processes, necessary for successful work, in already available systems of accounting or CRM, and in what fundamental difference of BPMS from other options of automation of business processes is necessary.

In this article I want to tell about what is BPMS systems why they are necessary and what process approach differs from traditional methods of work in. I will not speak about technical aspects of BPMS (about modeling and development of business processes), the following article will be devoted to it. Now I will try to reveal entity and sense of BPMS the most simple and clear language:

Read more »


Under Redis cowl: Hash table (part 2) and List

1 year, 1 month ago
In the first part I told that a hash the table is a few LIST, SET and SORTED SET. You judge — LIST consists of ziplist/linkedlist, SET consists of dict/intset, and SORTED SET is ziplist/skiplist. We already considered the dictionary (dict), and in the second part of article we will consider structure of ziplist — the second most often applicable structure under Redis cowl. Let's look at LIST — the second part of its "kitchen" is simple implementation of the chained list. It is useful to us attentively to consider often mentioned council about optimization a hash of tables through their replacement by lists. Let's consider how many it is required to memory on overhead costs when using these structures what price you pay for economy of memory. Let's sum up the results during the work about a hash as tables, when using the coding in ziplist.

Last time we finished that ziplist of 1,000,000 keys saved with use occupied 16 MB of random access memory whereas in dict the same data demanded 104 MB (ziplist 6 times less!). Let's understand what price:

Read more »


About systems thinking

1 year, 1 month ago
It is the first post from a series about systems thinking and system engineering in which I will try to describe a simple language these abrupt pieces and to explain why they are necessary.

Systems thinking is a practical approach to perception of the world which considerably accelerates capabilities to analyze, make decisions and to study. Practical because it is created by practice, but did not grow from abstract mathematical theories.

If TRIZ abbreviation is familiar to you, then I would tell that the TRIZ methods are a set of special cases of application of systems thinking in physical production.

Read more »


50 typical errors of design of the game camera (part 1)

1 year, 1 month ago
image

This article — transfer of performance of John Neski (John Nesky) with GDC14.

John — one of developers in the TGC company known for the game Journey. It began to work as the game designer there, but afterwards was fond of setup of operation of the camera in Journey therefore now his position sounds as Feel Engineer.


It is unlikely you will find some community of the developers specializing in game cameras. Also there is, perhaps, only one book on this subject — Real Time Cameras behind Mark Heyg-Hutchinson (Mark Haigh-Hutchinson) authorship. But it would be desirable to study more deeply this subject and to learn how people solve these or those difficulties.

The fact that the great attention is not riveted on a subject of cameras is unsurprising — so far they work as it is necessary, to discuss them there is no need. They become noticeable when do something not so. Players begin to discuss operation of the camera only when want to complain that it irritates them.

Therefore to talk on game cameras, it is necessary to reconcile to errors. And in this article I will tell what can go not so when you begin to project behavior of the camera in your game.

Read more »