E-commerce Fundamentals: A True/False and Multiple Choice Quiz
TRUE/FALSE.
Write ‘T’ if the statement is true and ‘F’ if the statement is false.
1) E-commerce technologies provide a unique, many-to-many model of mass communication. T
2) Ubiquity lowers the cognitive energy required to transact in a marketspace. T
3) The fact that e-commerce is conducted on the basis of universal standards increases search costs for consumers. F
4) Cost transparency refers to the ease with which consumers can find out the variety of prices in a market. T
5) Universal standards make
Read MoreRMI Architecture and Hibernate Implementation Guide
RMI Architecture
Controller
1) Controller instance
2) BusinessDelegate Server. Create controller, in the Controller setServer(new BusinessDelegate());, in the methods add BusinessException and Remote Excp.
Business Delegate
1) Class implements IAppRemote
2) IAppRemote BusinessService.
setBusinessService( (IAppRemote) Naming.lookup(IAppRemote.URL_SERVICIO) );
} catch (Exception e) {
throw new BusinessException(e.getMessage());
BusinessException
BusinessException extends Exceptions implements Serializable. BusinessException(
Read MoreDC-DC Converters and Battery Characteristics
DC-DC Converter Analysis
Boost Converter
A boost DC-DC converter switches at 100 kHz. The input is +12 V and the duty ratio of the transistor is 75%. The input inductor is 25 μH, and the output capacitor is 100 μF. If the load draws 50 W, the output voltage is found to be 48 V.
Output Voltage Calculation
What is the output voltage for a 10 W load? If L > Lcrit and C > Ccrit, then Vout/Vin = 1/D2. With a 50 W load, Vout = 48 V. This gives D2 = 0.25, so it would be continuous mode. For a 10 W
Read MorePneumatic Compressors and Valves: Types & Applications
Pneumatic Compressors
Piston Compressor
This compressor sucks in air at atmospheric pressure and then compresses it. It consists of intake and exhaust valves, a piston, and a connecting rod-crank mechanism.
Admission:
The shaft rotates clockwise. The crank pulls the piston down, and the intake valve lets air in 10º after Top Dead Center (TDC) until Bottom Dead Center (BDC).
Escape:
At BDC, the intake valve closes, and as the piston ascends, it compresses the air. Under pressure, the exhaust valve opens
Read MoreEnergy and Its Transformations: A Comprehensive Guide
Energy and Its Transformations
Energy Sources and Transformations
We obtain energy from primary energy sources and transform it daily. We can use energy in its primary form (e.g., wind’s kinetic energy to move a boat). We distinguish between primary, intermediate, and useful energies. For example, an engine transforms the chemical energy of petrol (primary) into heat (intermediate), which can then be transformed into kinetic energy (useful). The most common intermediate energy is electricity.
Types
Read MoreIntroduction to Geographic Information Systems (GIS)
Vector and Raster Data in GIS
The digital GIS representations of geographic features are called vector and raster data. Vector data are designed for discrete objects and are represented with pairs of x, y coordinates.
- Point features have a single pair of coordinates. Examples include a tree or an electric pole.
- Lines are represented with a start node and a stop node, and usually several vertices between these nodes, all having defined positions (pairs of x, y coordinates). Examples include roads or