Difference between == and .equals() in Java:

== is used to compare the memory addresses of objects, while .equals() compares the contents of objects.

Example: 

String str1 = new String("Hello");

String str2 = new String("Hello");

System.out.println(str1 == str2); // false (different memory addresses)

System.out.println(str1.equals(str2)); // true (same content)

Grid Computing

Features of Grid Computing:

• Resource sharing: Grid computing facilitates the sharing of computing resources, including processing power, storage capacity, and software applications, among multiple users and organizations.
• Scalability: Grid computing provides scalability by allowing additional resources to be easily added or removed from the grid as per the demand.
• Collaboration: Grid computing promotes collaboration among different organizations or research groups. It enables them to share data, tools, and expertise, leading to enhanced research capabilities and faster discovery.
• Fault tolerance: Grid computing systems are designed to be resilient and fault-tolerant. If a node or resource fails, the workload can be automatically rerouted to another available resource, ensuring minimal disruption and downtime.
• Heterogeneity: Grid computing supports the integration of diverse computing resources and platforms, including different operating systems, hardware architectures, and software stacks.

Drawbacks of Grid Computing:

• Complexity: Setting up and managing a grid computing infrastructure can be complex and require specialized skills.
• Security and privacy: Grid computing involves sharing resources across multiple organizations, which introduces security and privacy concerns.
• Performance variability: Grid computing relies on resources that may have varying capabilities, network latencies, and bandwidth limitations.
• Interoperability: Achieving interoperability between different software platforms, tools, and applications within a grid environment can be challenging.

Big Data Analytics

Key aspects of Big Data Analytics:

1. Data collection and storage: Big Data analytics requires collecting, storing, and managing massive volumes of data from various sources.
2. Data preprocessing: Before analysis, Big Data often requires preprocessing, which involves cleaning, filtering, transforming, and integrating data from different sources.
3. Data analysis techniques: Big Data analytics employs various techniques such as statistical analysis, data mining, machine learning, natural language processing, and predictive modeling.
4. Real-time and batch processing: Big Data analytics can be performed in real-time or using batch processing.
5. Visualization and reporting: The results of Big Data analytics are often visualized and presented in a meaningful way to facilitate understanding and decision-making.

AI (Artificial Intelligence) refers to the simulation of human intelligence in machines that are designed to think and act like humans. AI is used in various industries to automate repetitive tasks, make predictions, and solve complex problems. 

Here are a few examples of how AI is being used in different industries:

1. Healthcare: AI is being used in healthcare for medical imaging analysis, drug discovery, and personalized treatment plans.
2. Finance: AI is being used in finance for fraud detection, credit scoring, and algorithmic trading.
3. Retail: AI is being used in retail for personalized recommendations, demand forecasting, and supply chain optimization.
4. Transportation: AI is being used in transportation for autonomous vehicles, traffic management, and route optimization.
5. Manufacturing: AI is being used in manufacturing for predictive maintenance, quality control, and process optimization.
6. Customer Service: AI-powered chatbots are being used in customer service for handling basic queries, improving response times, and providing 24/7 support.

These are just a few examples of the many ways AI is being used to drive efficiency, make better decisions, and create new products and services across different industries.

To apply for an internship in Mejona, follow the steps given below.

Go to home page  >>  Menu  >> Careers >> Click Apply.

or directly click on this link https://mejona.com/career.php​​

"MEJONA is an ISO-certified IT Company registered under MSME & MCA that operates via websites and mobile apps. Mejona is a unit of MEJONA Technology LLP.

MEJONA is an E-learning website that provides Educational services, technical training, skill development, and internships. Launched on Sep 1, 2021, the platform is primarily used for professional networking, Educational Services, and career development. It allows students to clear their doubts by raising their queries and experts explain the questions raised by students."

ADVANTAGES:

1) Coal: as present is cheap.

2) Security: by storing certain quantity, the energy availability can be ensured for a certain period.

3) Convenience: it is very convenient to use.

DISADVANTAGES:

1) Fossil fuels generate pollutants: CO, CO2, NOX, SOX. Particulate matter & heat. The pollutants degrade the environment, pose health hazards & cause various other problems.

2) Coal: it is also valuable petro-chemical & used as source of raw material for chemical, pharmaceuticals & paints, industries, etc. From long term point of view, it is desirable to conserve coal for future needs.

3) Safety of nuclear plants: it is a controversial subject.

4) Hydro electrical plants are cleanest but large hydro reservoirs cause the following problems.

a) As large land area submerges into water, which leads to deforestation.

b) Causes ecological disturbances such as earthquakes.

c) Causes dislocation of large population & consequently their rehabilitation problem.

Merits:

1. NCES are available in nature, free of cost.

2. They cause very little pollution. Thus, by and large, they are environmental friendly.

3. They are inexhaustible.

4. They have low gestation period.

Demerits:

1) Though available freely in nature, the cost of harnessing energy from NCES is high, as in general, these are available in dilute forms of energy.

2) Uncertainty of availability: the energy flow depends on various natural phenomena beyond human control.

3) Difficulty in transporting this form of energy.

1. Based on usability of energy:

a) Primary resources:

Resources available in nature in raw form is called primary energy resources. Ex: Fossil fuels (coal, oil & gas), uranium, hydro energy. These are also known as raw energy resources.

b) Intermediate resources: This is obtained from primary energy resources by one or more steps of transformation & is used as a vehicle of energy.

c) Secondary resources: The form of energy, which is finally supplied to consume for utilization. Ex: electrical energy, thermal energy (in the form of steam or hot water), chemical energy (in the form of hydrogen or fossil fuels). Some form of energies may be classified as both intermediate as well as secondary sources. Ex: electricity, hydrogen.

2. Based on traditional use:

a) Conventional: Energy resources which have been traditionally used for many decades. Ex: fossil fuels, nuclear & hydro resources

b) Non-conventional: Energy resources which are considered for large scale & renewable. Ex : solar, wind & bio-mass

3. Based on term availability:

a) Non-renewable resources: resources which are finited, & do not get replenished after their consumption. Ex : fossil fuels, uranium

b) Renewable resources: resources which are renewed by nature again & again & their supply are not affected by the rate of their consumption. Ex : solar, wind, biomass, ocean ( thermal, tidal & wave), geothermal, hydro

4. Based on commercial application:

a) Commercial energy resources: the secondary useable energy forms such as electricity, petrol, and diesel are essential for commercial activities. The economy of a country depends on its ability to convert natural raw energy into commercial energy. Ex : coal, oil, gas, uranium, & hydro

b) Non-commercial energy resources: the energy derived from nature & used – directly without passing through commercial outlet. Ex: wood, animal dung cake, crop residue.

5. Based on origin:

a) Fossil fuels energy     f) bio-mass energy

b) Nuclear energy          g) geothermal energy

c) Hydro energy             h) tidal energy

d) Solar energy               i) ocean thermal energy

e) Wind energy               j) ocean wave energy

The concern for environmental due to the ever increasing use of fossil fuels & rapid depletion of these resources has led to the development of alternative sources of energy, which are renewable & environmental friendly. Following points may be mentioned in this connection.

1) The demand of energy is increasing by leaps & bounds due to rapid industrialization & population growth, the conventional sources of energy will not be sufficient to meet the growing demand.

2) Conventional sources (fossil fuels, nuclear) also cause pollution; there by their use degrade the environment.

3) Conventional sources (except hydro) are non-renewable & bound to finish one day.

4) Large hydro-resources affect wild-life, cause deforestation & pose various social problems, due to construction of big dams.

5) Fossil fuels are also used as raw materials in the chemical industry (for chemicals, medicines, etc) & need to be conserved for future generations.

Due to these reasons it has become important to explore & develop nonconventional energy resources to reduce too much dependence on conventional resources. However, the present trend development of nces indicates that these will serve as supplements rather than substitute for conventional sources for some more time to time.

USB  Universal Serial Bus (USB) is an industry standard developed through a collaborative effort of several computer and communication companies, including Compaq, Hewlett-Packard, Intel, Lucent, Microsoft, Nortel Networks, and Philips.

 Speed -

 Low-speed(1.5 Mb/s)

 Full-speed(12 Mb/s)

 High-speed(480 Mb/s)

 Port Limitation

 Device Characteristics

 Plug-and-play USB TREE STRUCTURE 

 To accommodate a large number of devices that can be added or removed at any time, the USB has the tree structure as shown in the figure.

 Each node of the tree has a device called a hub, which acts as an intermediate control point between the host and the I/O devices. At the root of the tree, a root hub connects the entire tree to the host computer. The leaves of the tree are the I/O devices being served (for example, keyboard, Internet connection, speaker, or digital TV)

 In normal operation, a hub copies a message that it receives from its upstream connection to all its downstream ports. As a result, a message sent by the host computer is broadcast to all I/O devices, but only the addressed device will respond to that message. However, a message from an I/O device is sent only upstream towards the root of the tree and is not seen by other devices. Hence, the USB enables the host to communicate with the I/O devices, but it does not enable these devices to communicate with each other.

 When a USB is connected to a host computer, its root hub is attached to the processor bus, where it appears as a single device. The host software communicates with individualdevices attached to the USB by sending packets of information, which the root hub forwards to the appropriate device in the USB tree.

 Each device on the USB, whether it is a hub or an I/O device, is assigned a 7-bit address. This address is local to the USB tree and is not related in any way to the addresses used on the processor bus.

 A hub may have any number of devices or other hubs connected to it, and addresses are assigned arbitrarily. When a device is first connected to a hub, or when it is powered on, it has the address 0. The hardware of the hub to which this device is connected is capable of detecting that the device has been connected, and it records this fact as part of its own status information. Periodically, the host polls each hub to collect status information and learn about new devices that may have been added or disconnected.

 When the host is informed that a new device has been connected, it uses a sequence of commands to send a reset signal on the corresponding hub port, read information from the device about its capabilities, send configuration information to the device, and assign the device a unique USB address. Once this sequence is completed the device begins normal operation and responds only to the new address. USB protocols

 All information transferred over the USB is organized in packets, where a packet consists of one or more bytes of information. There are many types of packets that perform a variety of control functions.

 The information transferred on the USB can be divided into two broad categories: control and data.

 Control packets perform such tasks as addressing a device to initiate data transfer, acknowledging that data have been received correctly, or indicating an error.  Data packets carry information that is delivered to a device.  A packet consists of one or more fields containing different kinds of information. The first field of any packet is called the packet identifier, PID, which identifies the type of that packet.  They are transmitted twice. The first time they are sent with their true values, and the second time with each bit complemented

 The four PID bits identify one of 16 different packet types. Some control packets, such as ACK (Acknowledge), consist only of the PID byte.

ELECTRICAL CHARACTERISTICS

 The cables used for USB connections consist of four wires.

 Two are used to carry power, +5V and Ground.

 Thus, a hub or an I/O device may be powered directly from the bus, or it may have its own external power connection.

 The other two wires are used to carry data.

 Different signaling schemes are used for different speeds of transmission.

 At low speed, 1s and 0s are transmitted by sending a high voltage state (5V) on one or the other o the two signal wires. For high-speed links, differential transmission is used.