Design Patterns

Article contributed by Mr. Manoj Singh Bisht, Assistant Professor, Faculty of Technology and Computer Applications

The Industry demand for highly flexible system that can respond to quick and never ending changes of rapidly changing technology world is a major challenge for today’s software design and development.

 To answer the magic word “Change is constant” in software design the “Gang of Four” came up with a fantastic solution “Design Patterns: Elements of Reusable Object-Oriented Software” published in 1994. They provided a collection of best practices for frequent real world problems, that software designers, developers, architects faces while developing software. Referencing these patterns an Architect can draw a road map of a software considering issues that may become visible later in the implementation phase. Design patterns can help in seamless design and implementation of software without facing commonly occurring problem in software design.

 A highly flexible system that can achieve the business goals and can rapidly restructure itself with the new business goals can be designed referencing patterns such as Creational, Structural, Behavioral patterns. These patterns or best practices has changed the software designed techniques and has made obsolete the well known principle of inheritance and recommended the object composition mechanism, pushed developers to interface programming.

 Referencing the right pattern from multiple patterns such as Factory, Abstract Factory ,Builder ,Prototype ,Singleton ,Adaptor, Bridge ,Decorator, Façade, Visitor etc as per the need of software the ” Gang of Four” made easy the life of software designers, Business leads, developers, Architects and provided a common language platform to all for easy communication and common understandability.

Some critics are there, that say’s that design patterns provide solution for limited or certain problems they can’t address all range of problems. But design patterns are general solutions, they are tested on multiple projects, with error and trial and now they are at matured stage helping and providing a new height to robust and flexible software development.

Li-Fi (Light Fidelity)

Article contributed by Mr. Vinod Mishra, Assistant Professor, Faculty of Technology and Computer Applications

Li-Fi is a wireless optical networking technology that uses visible light from LED’s for data transmission. Li-Fi is a communication system which is capable of data transmission at high speed over the visible light, ultraviolet and infrared spectrum. At present only LED lamps can be used for the transmission of visible light [1] . it is similar to Wi-Fi the only difference is that Wi-Fi uses radio frequency to transmit data whereas Li-Fi uses visible light. Li-Fi provides several advantages over Wi-Fi most important is wider bandwidth and higher transmission speed[2]. The visible light spectrum is 10,000 times larger than the entire radio frequency spectrum so it has no capacity limitation [3] . Li-Fi is expected to be 10 times cheaper than Wi-Fi[4]

Li-Fi is more useful in aircraft cabins, hospitals and  nuclear power plants for avoiding electromagnetic interference[5]

It is predicted that in future home and building automation will be highly dependent on the Li-Fi technology as it is very secure and fast. As light cannot penetrate through walls, the signal can not be hacked from a remote location.

The block digram of simple Li- Fi system is as given below.

Block diagram of Li-Fi System

The transmitter section includes the input, timer circuit and an LED bulb. The input of the transmitter can be any kind of data like text, voice. The timing circuit provides the necessary time interval among every bit and these are transmitted to the receiver end in the form of LED flashes.

The Receiver section includes photodiodes as well as amplifier.

Photodiode receives the LED bulb flashes then chenges the flashes in to electrical signals.

Amplifier receives the signal from the photodiode and amplifies to provide the output.

Difference between Li-Fi and Wi-Fi

Features Li-Fi Wi-Fi
Work of operation Transmission of data using LED bulb Transmission of data using radio waves
Technology Present IrDA(Infrared Data Association) WLAN(802.a/b/g/n)
Interference No intrference Interference issue from nearby access point
Transmission security more secure data transfer require security technique
Data Transfer Speed Data transfer speed between 1Gbps to 20 Gbps 150 Mbps with WLAN11n
Frequency of operation 10,000 times frequency spectrum of radio waves 2.4GHz, 4.9GHz and 5 GHz
Data Density work in high dense environment work in less dense environment
Distance Coverage 10 meter 32 meter
System components lamp driver, LED bulb and photodetector Router

Application of Li-Fi

As Li-Fi uses light  from LED which cannot penetrate through walls and doors . this makes it more secure and it can be used in variety of application.

Aviation– Li-Fi based data transmission will not interfere with equipment on the Aircraft.

Hospital- Li-Fi system could be better system which has little effect on medical instrument.

Vehicles- Vehicles could communicate with one another via front and back light to increase road safety.

Industrial Automation- It can be used in Industry by replacing cables for communication.


“Comprehensive Summary of Modulation Techniques for LiFi | LiFi Research”. Retrieved 16 January 2018.

2. “Li-Fi can transmit upto 100 gbps data,due to its wider bandwidth”

3.Haas,Harald (19 April 2013)“High-speed wireless networking using visible light”.SPIE Newsroom. doi:10.1117/2.1201304.004773.

4. Condliffe, Jamie (28 July 2011). “Will Li-Fi be the new Wi-Fi?”. New Scientist. Archived from the original on 31 May 2015.

5.Li-Fi Internet at the Speed of Light, by Ian Lim, the gadgeteer, dated 29 August 2011 Archived 1 February 2012 at the Wayback Machine


Article contributed by Mr. Ashish Upreti, Assistant Professor, Faculty of Technology and Computer Applications

Natural resources(petroleum and its products), while getting transformed into heat energy generate environmentally harmful products like CO, CO2, NOx, HC etc. causing a detrimental effect to the environment including ecosystem and ecology, indirectly and directly, to the health of living beings. Directly through air pollution (inhalation of harmful gases, smog formation etc.) and water pollution (industrial waste water, agricultural runoff, municipal sewage etc.), while indirectly through degradation of ecosystem, natural hazards, ozone depletion etc.

Thus summarizing the changes that occur to the functioning of earth system is as follows:

  1. Disruptions to the global climate.
  2. Depletion of stratospheric ozone.
  3. Irreversible losses of biological diversity.
  4. Changes in the structure and functioning of ecosystem around the world.

Biofuel is any liquid fuel made from plant that can be used as a substitute for petroleum-derived fuel. Biodiesel is a biofuel which is  derived from renewable feed stocks. There are ten plant species for biodiesel production some of them are Jatropha curcas, Madhuca indica (Mahua), Pongamia pinnata, Azadirachta indica (Neem) and Simarouba glauca. Biodiesel can be produced by  transesterification process where vegetable oil or animal fat react in presenceof a catalyst  with an alcohol(methanol or ethanol) to give biodiesel and glycerin as a byproduct.

Biodiesel can solve India’s many problems. First, asagricultural growth lags behind growth in manufacturing and servicesdue to lack of investment and low productivity,which can only be arrested by stimulating rural development . About 70% of India’s poor people live in rural areas, and their probability to overcome poverty during one generation are dim . Also, spending on  imports of petroleum send dollars out of our country thereby reducing our foreign exchange. Biodiesel production shift this spending from foreign imports to domestically produced energy. Wastelands, degraded forest land and land with scrub vegetation could be the regions where  oil-bearing trees can be planted. It also offers new energy-related markets to farmers.

Second, India’s oil imports causes a huge expenditure and creating a deficit in balance of payments and increasing the share in GDP. India’s oil import will rise by 93 %. Also, emissions will rise to 3000 mt by 2020, making India the third largest emitter worldwide, after the United States and China.

Third,  the supply of crude oil and natural gas is limited. Biodiesel has the potential to replace the limited supplies of fossil fuels.

Also, India will equal the size of the US economy by 2040 and exceed its economy in 2050, so to cope with energy deficit, to have it’s economy continuously rising and to provide a suitable habitat to the next generation use ofalternate ecofriendly fuel is a necessity .

The smog formation and emission of carbon monoxide, hydrocarbons, PAH and nPAH compounds were greatly reduced by using Biodiesel.There are significant reductions in  emissions : 99 % reduction in SOxemissions,20% reduction in CO, 32% reduction in HC, 50% reduction in soot and 39% reduction in particulate matter.

Overall benefits of biodiesel over diesel fuelinclude displacement of imported petroleum, lower toxicity and exhaust emissions, derivation from renewable feedstocks, very small sulfur and aromatics content, superior lubricity and biodegradability, and a positive energy balance.