Wednesday, June 11, 2008

Cybernetics

Cybernetics is the interdisciplinary study of the structure of complex systems, especially communication processes, control mechanisms and feedback principles. Cybernetics is closely related to control theory and systems theory.

Example of cybernetic thinking. On the one hand a company is approached as a system in an environment. On the other hand cybernetic factory can be modeled as a control system.

Example of cybernetic thinking. On the one hand a company is approached as a system in an environment. On the other hand cybernetic factory can be modeled as a control system.

Contemporary cybernetics began as an interdisciplinary study connecting the fields of control systems, electrical network theory, mechanical engineering, logic modeling, evolutionary biology and neuroscience in the 1940s.

Other fields of study which have influenced or been influenced by cybernetics include game theory, system theory (a mathematical counterpart to cybernetics), psychology (especially neuropsychology, behavioral psychology, cognitive psychology), philosophy, and architecture.

Monday, June 02, 2008

Cellular automaton

A cellular automaton (plural: cellular automata) is a discrete model studied in computability theory, mathematics, theoretical biology and microstructure modeling. It consists of a regular grid of cells, each in one of a finite number of states. The grid can be in any finite number of dimensions. Time is also discrete, and the state of a cell at time t is a function of the states of a finite number of cells (called its neighborhood) at time t − 1. These neighbors are a selection of cells relative to the specified cell, and do not change (though the cell itself may be in its neighborhood, it is not usually considered a neighbor). Every cell has the same rule for updating, based on the values in this neighbourhood. Each time the rules are applied to the whole grid a new generation is created.

Tuesday, May 27, 2008

Conceptual system
A conceptual system is simply a model. There is no limitations on this kind of model whatsoever except those of human imagination. If there is an experimentally verified correspondence between a conceptual system and a physical system then that conceptual system models the physical system. "values, ideas, and beliefs that make up every persons view of the world": that is a model of the world; a conceptual system that is a model of a physical system (the world). The person who has that model is a physical system.

In psychology and social work, when they talk about a conceptual system, they are referring to some person's model of the world, but if they try to understand that model, they end up making a model of that model, which is just a model of the person's behavior. In any case, this is exactly the purpose of the general term "conceptual systems".

Monday, May 19, 2008

Systems engineering


Systems engineering is an interdisciplinary field of engineering, that focuses on the development and organization of complex artificial systems. Systems engineering is defined by INCOSE as "a branch of engineering whose responsibility is creating and executing an interdisciplinary process to ensure that customer and stakeholder's needs are satisfied in a high quality, trustworthy, cost efficient and schedule compliant manner throughout a system's entire life cycle, from development to operation to disposal. This process is usually comprised of the following seven tasks: State the problem, Investigate alternatives, Model the system, Integrate, Launch the system, Assess performance, and Re-evaluate. The systems engineering process is not sequential: the tasks are performed in a parallel and iterative manner."

Monday, May 12, 2008

Concurrent Versions System

In the field of software development, the Concurrent Versions System (CVS), also known as the Concurrent Versioning System, provides a version control system based on open-source code. Version control system software keeps track of all work and all changes in a set of files, and allows several developers (potentially widely separated in space and/or time) to collaborate. Dick Grune developed CVS in the 1980s. CVS has become popular in the open source software world and is released under the GNU General Public License.

Tuesday, May 06, 2008

Solutrean hypothesis

The Solutrean hypothesis proposes that stone tool technology of the Solutrean culture in prehistoric Europe may have later influenced the development of the Clovis tool-making culture in the Americas, and that peoples from Europe may have been among the earliest settlers in the Americas. First proposed in 1998, its key proponents include Dennis Stanford of the Smithsonian Institution and Bruce Bradley of the University of Exeter.

In this hypothesis, peoples associated with the Solutrean culture migrated from Ice Age Europe to North America, bringing their methods of making stone tools with them and providing the basis for later Clovis technology found throughout North America. The hypothesis rests upon particular similarities in Solutrean and Clovis technology that have no known counterparts in Eastern Asia, Siberia or Beringia, areas from which or through which early Americans are known to have migrated.

Monday, April 28, 2008

Green travel

Green travel is a method for people to travel while reducing their impact on the environment.

Some forms of green travel include:

* Use of walking, cycling, and public transport instead of car use, when possible.

* Use of biodiesel fuels.

* Taking advantage of ridesharing and carpools

* Booking travel through a green website like Green Travel by RezHub.com . They not only offers bookings with green travel suppliers (hotels, hybrid car rentals, carbon offstting), they also donate a portion of all revenue to a green organization.

* Stay at a green hotel or lodge.

Monday, April 21, 2008

Transformation of culture

Transformation of culture, or cultural change, refers to the dynamic process whereby the living cultures of the world are changing and adapting to external or internal forces. This process is occurring within Western culture as well as non-Western and indigenous culture of the world. Forces which contribute to the cultural change described in this article include: colonization, globalization, advances in communication, transportation and infrastructure improvements, and military expansion.
Transformation of culture

Transformation of culture, or cultural change, refers to the dynamic process whereby the living cultures of the world are changing and adapting to external or internal forces. This process is occurring within Western culture as well as non-Western and indigenous culture of the world. Forces which contribute to the cultural change described in this article include: colonization, globalization, advances in communication, transportation and infrastructure improvements, and military expansion.

Monday, April 14, 2008

Evolutionary prototyping

Evolutionary Prototyping (also known as breadboard prototyping) is quite different from Throwaway Prototyping. The main goal when using Evolutionary Prototyping is to build a very robust prototype in a structured manner and constantly refine it. "The reason for this is that the Evolutionary prototype, when built, forms the heart of the new system, and the improvements and further requirements will be built

When developing a system using Evolutionary Prototyping, the system is continually refined and rebuilt.

"…evolutionary prototyping acknowledges that we do not understand all the requirements and builds only those that are well understood."

Monday, April 07, 2008

Life cycle of a relational database

The life cycle of a relational database is the cycle of development and changes that a database goes through during the course of its life. The cycle typically consists of several stages. There is possibility that the database designer/developer can go back to any of the previous stages. This represents an admission that a full understanding of a problem and its solution is likely to evolve as the various stages of design and implementation proceed. The typical eleven stages involved in the life cycle of a relational database are as follows:

BE AWARE THIS IS ONLY ONE VERSION, MULTIPLE DIFFERING VERSIONS EXIST

1. The designer must try to obtain as complete as possible an understanding of the real world problem that is going to be helped by the introduction of a database. This understanding of the nature of the problem and the constraints and outline feasible solutions is often performed using some systems analysis methodology.
2. The entity relationship diagram is drawn, and this diagram in its modified form serves as an essential part of the logical schema. Attributes of the entity types so produced are then added. Primary and foreign keys are specified.
3. Normalization is used to check the entity-relationship model. Some splitting and even recombination of entity types may result from normalization and the entity relationship model will have to be updated accordingly. The entity relationship model and the table definitions resulting from normalization should be consistent.
4. Set of Table(s) definition for the required schema is finalized.
5. The database tables are created. Primary, Foreign keys, database constraints and database integrity rules are specified at this stage.
6. At this stage, the file organization is performed. File organization is the way the database relations are to be stored on the storage medium. The file organization is decided on the basis of maximum speed of access, the type of access required and storage space considerations. There are two factors to consider; firstly how the records are to be physically mapped onto the storage medium, and secondly which indexes are to be used and if so, which fields (attributes, columns) are to be indexed. Indexes are designed to increase the speed of access to required records. Views can also be defined at this stage. Views are used to limit access to parts of database only, when used in conjunction with access privileges. Views also make programming simpler.
7. The designer will be able to design the required queries at this stage. The designer should have a good idea of the main types of query and reports the database will have to accommodate.
8. At this stage, application screens are designed. The application screens are used to capture the input information that will be kept in the database. Screen design is partially determined by the data items that must be input and output by particular applications and partially in human-computer interface terms. When designing screens, special consideration is given to the suggestions given by the application end users. There are published standards which can be exactly followed for screens design or organization can develop their own screen design standards as per their requirements.
9. Report design is another area where input from users is paramount. They will specify what they want to see on the reports and the format of the reports and in the case of regular reports, when they should be produced. Now-a-days most of the application design tools provide easy to use friendly tools for quick reports development. e.g. report builder in Oracle, Crystal Reports, R&R Report Writer etc.
10. Testing is performed at this stage. Application screens, various functions offered by the application screens, data validations through screens and reports are tested and it serves as the ultimate test of the correctness of the database schema and the viability of the system as a whole. It is recommended to create a test database separate of the production database. The test database will be useful for testing any schema changes and new and modified application before applying the changes to the production (live) database. Careful testing of the system before handover will minimize the expense of later modifications to the schema and major applications.
11. The final stage is Handover. This is the stage where the users receive the finished database and applications and begin data entry. In practice, it is likely that the core of the system will be handed over to users and later extensions to the system will be implemented.

Friday, April 04, 2008

4th Dimension (Software)


4th Dimension (or 4D, or Silver Surfer, as it was known during early development) is a relational database management system and IDE developed by Laurent Ribardière in 1984. In 1993, 4D Server, the client/server version of 4th Dimension was introduced and since 1995, 4D has supported both the Microsoft Windows and Apple Macintosh operating systems.

The 4D product line has since expanded to an SQL front-end, integrated compiler and several productivity plug-ins and interfaces. Some of the more useful plug-ins include 4D Write (a word processor), 4D Draw (to draw shapes), 4D View (somewhat like a spreadsheet, but with extra functionality) and 4D Internet Commands (which let you add all sorts of Internet related functionality to a database). There are also over 100 third-party plugins, free and commercial.

Monday, March 24, 2008

Application-level gateway

In the context of computer networking, an application-level gateway [1] (also known as ALG or application layer gateway) consists of a security component that augments a firewall or NAT employed in a computer network. It allows customized NAT traversal filters to be plugged into the gateway to support address and port translation for certain application layer "control/data" protocols such as FTP, BitTorrent, SIP, RTSP, file transfer in IM applications etc. In order for these protocols to work through NAT or a firewall, either the application has to know about an address/port number combination that allows incoming packets, or the NAT has to monitor the control traffic and open up port mappings (firewall pinhole) dynamically as required. Legitimate application data can thus be passed through the security checks of the firewall or NAT that would have otherwise restricted the traffic for not meeting its limited filter criteria.

Monday, March 17, 2008

Waterfall model
The waterfall model is a sequential software development model (a process for the creation of software) in which development is seen as flowing steadily downwards (like a waterfall) through the phases of requirements analysis, design, implementation, testing (validation), integration, and maintenance. The origin of the term "waterfall" is often cited to be an article published in 1970 by Winston W. Royce (1929–1995),[1] although Royce did not use the term "waterfall" in this article. Ironically, Royce was actually presenting this model as an example of a flawed, non-working model (Royce 1970).

Sunday, March 09, 2008

Field emission display (FED)

A field emission display (FED) is a type of flat panel display using field emitting cathodes to bombard phosphor coatings as the light emissive medium.

Field emission displays are very similar to cathode ray tubes, however they are only a few millimeters thick. Instead of a single electron gun, a field emission display (FED) uses a large array of fine metal tips or carbon nanotubes (which are the most efficient electron emitters known), with many positioned behind each phosphor dot, to emit electrons through a process known as field emission. Because of emitter redundancy, FEDs do not display dead pixels like LCDs even if 20% of the emitters fail. Sony is researching FED because it is the flat-panel technology that comes closest to matching the picture of a CRT.

Tuesday, March 04, 2008

Methods for solids

Computational chemical methods can be applied to solid state physics problems. The electronic structure of a crystal is in general described by a band structure, which defines the energies of electron orbitals for each point in the Brillouin zone. Ab initio and semi-empirical calculations yield orbital energies, therefore they can be applied to band structure calculations. Since it is time-consuming to calculate the energy for a molecule, it is even more time-consuming to calculate them for the entire list of points in the Brillouin zone.

Monday, February 25, 2008

Satur

Saturn (pronounced /'sæt?n/) is the sixth planet from the Sun and the second largest planet in the Solar System, after Jupiter. Along with the planets Jupiter, Uranus, Neptune it is classify as a gas giant (also known as a Jovian planet, after the planet Jupiter). It was named after the Roman god Saturnus, equate to the Greek Kronos (the Titan father of Zeus) and the Babylonian Ninurta. Saturn's sign represents the god's sickle (Unicode: ?), The day in the week Saturday gets its name from the planet.

The planet Saturn is calm of hydrogen, with small proportions of helium and trace elements. The interior consists of a small core of rock and ice, bounded by a thick layer of metallic hydrogen and a gaseous outer layer. The outer atmosphere is normally bland in appearance, although long-lived features can appear. Wind speeds on Saturn can reach 1,800 km/h, considerably faster than those on Jupiter. Saturn has a planetary magnetic field intermediate in strength among that of Earth and the more powerful field around Jupiter.

Tuesday, February 19, 2008

Pineapple

The pineapple (Ananas comosus) is a tropical plant and fruit (multiple), inhabitant to Uruguay, Brazil, Puerto Rico, or Paraguay. It is a medium tall (1–1.5 m) herbaceous perennial plant with 30 or more trough-shaped and pointed leaves 30–100 cm long, nearby a thick stem. The pineapple is an illustration of a multiple fruit: multiple, spirally-arranged flowers along the axis each make a fleshy fruit that becomes pressed against the fruits of adjacent flowers, forming what appears to be a single fleshy fruit. The leaves of the cultivar 'Smooth Cayenne' mostly lack spines apart from at the leaf tip, but the cultivars 'Spanish' and 'Queen' have large spines along the leaf margins. Pineapples are the only bromeliad fruit in extensive cultivation. It is one of the most commercially important plants which take out Crassulacean acid metabolism, or CAM photosynthesis.

Monday, February 11, 2008

Fixed asset

Fixed asset also familiar as property, plant, and equipment (PP&E), is a term used in accountancy for assets and goods which cannot easily be converted into cash. This can be differing with current assets such as cash or bank accounts, which are describe as liquid assets. In most cases, only tangible assets are also called as fixed.

It usually includes items such as land and buildings, motor vehicles, furniture, office tools, computers, fixtures and fittings, and plant and machinery. These frequently receive favorable tax treatment (deprecation allowance) over short-term assets because they depreciate in excess of time.

Monday, February 04, 2008

Soil

Soil, comprising the pedosphere, is located at the border of the lithosphere with the biosphere, atmosphere, and hydrosphere. It consists of mineral, organic matter, as well as living organisms. Soil formation, or pedogenesis, is the combined effect of physical, chemical, biological, and anthropogenic process on soil parent material ensuing in the configuration of soil horizons.
Soil is our most important natural resources because of its position in the landscape and its dynamic, physical, chemical, and biologic functions. While the general concept of soil is well recognized, the definition of soil varies, according to the viewpoint of the discipline or occupation by means of soil as a resource.