COVID-19 and the Impact on the Environment
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COVID-19 and the Impact on the Environment

As per the latest reports by the World Health Organisation, there is near about 20 lakh COVID-19 cases reported across the world so far, with a little over 1,26,776  deaths. In short, the corona virus has affected people’s life irrespective of their social and economic condition. In the thick of all the gloom and doom, there is a silver lining. Mother earth seems to have rejuvenated itself.Smog has given way to blue skies, marine life is improving, pollution levels have dropped, and animals as well as birds are moving about freely.

A few days ago, Noida’s busy Sector saw an unexpected guest. A Nilgai was seen walking slowly on the road. To the common man, this incident was a welcome change from the usually traffic jammed road. Similarly, in Kerala’s Kozhikode, a Malabar Civet, an endangered animal, was seen walking on the road.  Ever since the coronavirus pandemic struck across the globe, several reports have emerged highlighting the return of many species to their natural habitats.

The Government’s drastic decision to shut down factories, commercial establishments, and vehicular movement, has resulted in a drastic drop in the pollution levels across the world. As the pandemic continues to halt industrial activities, it has allowed a natural purification of air. Satellite images have proved that there has been considerable improvement in the air quality around us. Nature’s Victory! According to a research by Columbia University, both carbon monoxide and carbon-dioxide emissions were observed to have fallen.

The quiet street corners, empty parking lots, and deserted parks have given more space for nature to take control. The humdrum surrounding tourism and the reduced number of motorboats in Venice has led to cleaner waterways. The nationwide lockdown is also providing perfect condition for the Olive Ridley Turtles to lay eggs in Odisha’s Gahirmatha beach and Rushikulya’s rookery. Usually, this event is known to attract huge crowds and officials from the Forest Department generally deploy a considerable amount of efforts and resources to patrol gatherings, protect the eggs, and later release the hatchlings into the sea. However, this time, there were no such arrangements but nature has taken care of everything.

“COVID-19 has been an eye-opener. It has shown people as to how mother earth can bounce back to life if humans allow for it. But, unless the society cares for the environment and changes its attitude, all of it is bound to get back to square one,” – Ram Murthy.  However, is this a long-term trend? It is said that times of disruptions tend to lead to big transitions. The COVID-19 shutdown has given people a glimpse into what the world might look like if we live sustainably and conserve the resources of the planet. But, can people expect a transformation in the future? Nevertheless, the improvement in the air quality owing to the outbreak of the pandemic looks like a ray a ray of hope in the times to come.

Keywords:-COVID-19, Environment, social, economic, coronavirus

Name:- Mahesh S Waghmare,
Dept:- Department of Engineering Sciences
International Institute of Information Technology, Pune.

Flood Forecasting and Warning System
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Flood Forecasting and Warning System

Introduction: – The flood can occur anywhere after heavy rain. Flood forecasting sufficiently in advance enables a warning to be given to the people likely to be affected and further enable authorities to take appropriate precautionary measures. It thus forms a very important and relatively inexpensive non-structural flood management measure, however, it must be realized that a flood warning is meaningful only if it is given in advance. Further erroneous warnings will cause the populace to lose confidence and faith in the system. Thus the dual requirement of reliability and advance notice is the essential ingredient of a flood forecasting system.

Current Flooding Scenario in Maharashtra

MAHARASHTRA FLOOD 2019

Multiple parts of Maharashtra were battered by heavy rains that began during the second week of August 2019. The downpour particularly affected the districts of Kolhapur, Sangli, Satara, Thane, Pune, Nashik, Palghar, Ratnagiri, Raigad and Sindhudurg.

According to a report from August 12, rain and flood-related incidents had killed 35 people across the state. As many as 761 villages were affected, and more than 4 lakh people were displaced. To conduct rescue operations, multiple teams of the National Disaster Response Force (NDRF), Navy, Coast Guard, and State Disaster Response Force (SDRF) were deployed in the affected areas.

The Warna river at Samdoli in Sangli, the Krishna at Arjunwad in Sangli, and the Krishna at Kurunwad in Kolhapur were all flowing at record levels. In fact, floodwaters in Kolhapur and Sangli only began to recede after the flood gates of the Almatti dam were opened, which subsequently led to damage in Karnataka.

(Credits: Sachin Haralkar/BCCL Mumbai)

Causes of Flooding

There are several causes of floods and they differ from region to region. The causes may vary from a rural area to an urban area. Some of the major causes of floods in India are given below.

Heavy rainfall: It is the primary cause for floods in India. Especially, rainfall in a short span of time is of much concern as they are leading to flash floods. For instance, in July 2017, Mount Abu received the heaviest rainfall in over 300 years in a span of 24 hours. The hill station received an unprecedented 700 mm of rain in 24 hours. As per a study instituted by the United Nations, climate change phenomenon is believed to be behind flash floods across the globe.

Siltation of the Rivers: Heavy siltation of the riverbed reduces the water carrying capacity of the rivers and streams leading to flooding. For instance, as a result of siltation, the Brahmaputra has been expanding – ranging from 2 km to 14 km – leading to frequent flooding in the North East region

.Blockage in the Drains: Blocked drains are the primary cause for the floods in urban areas, especially in metros. For instance, failure of the drainage system is believed to be one of the primary causes behind the Chennai floods in December 2015 that led to the death of more than 400 people.

Impact of flooding

The most important consequence of floods is the loss of life and property. Structures like houses, bridges and roads get damaged by the gushing water.
Some of the negative impacts of recurrent floods are given below –

Impact on Agriculture: Recurrent floods impact the agriculture sector adversely. Due to recurrent floods, fields get submerged and lead to the loss of harvest increasing the vulnerability of farmers to indebtedness. The loss is not only for the farming community but also the common man is hit hardly due to persistent inflation. Besides, the threat to life of milch animals impact the farming community adversely.

Moreover, floods may also affect the soil characteristics. The land may be rendered infertile due to erosion of top-layer.

Damage to infrastructure: Recurrent floods cause severe damage to economic infrastructure like transportation networks, electricity generation and distribution equipment,etc.
Outbreak of diseases: Lack of proper drinking water facilities, contamination of water (well, ground water, piped water supply) leads to outbreak of epidemics like diarrhoea, viral infection, malaria and many other infectious diseases. The probability of outbreak of diseases in highly dense areas of India is high.

Besides the above, strain on the administration, cost of rescue and rehabilitation of the flood affected population are other causes of concern.

Remedial Measures

The solution to the problem of recurrent floods lies in mitigation and rehabilitation measures. Some of the important measures are given below.

  1. Mapping of the flood prone areas is a primary step involved in reducing the risk of the region. Historical records give the indication of the flood inundation areas and the period of occurrence and the extent of the coverage.
  2. Land use control will reduce danger of life and property when waters inundate the flood plains and the coastal areas.
  3. The number of casualties is related to the population in the area at risk. Hence, in areas where people already have built their settlements, measures should be taken to relocate to better sites so as to reduce vulnerability.
  4. No major development should be permitted in the areas which are subjected to high flooding. Important facilities like hospitals, schools should be built in safe areas. In urban areas, water holding areas can be created like ponds, lakes or low-lying areas.
  5. The buildings should be constructed on an elevated area. If necessary build on stilts or platform.
  6. The amount of runoff can be decreased with the help of reforestation, protection of vegetation, clearing of debris from streams and other water holding areas, conservation of ponds and lakes etc.
  7. Flood diversion measures like construction of levees, embankments and dams should be undertaken.

 

Conclusion:-

As per an estimate, 12% of India’s land is prone to floods. As per the Central Water Commission (CWC), floods resulted in a loss of 0.86% of the total GDP. However, in the present decade, this share has come down to 0.1% of the GDP. Taking into account the growing size of the economy, still, the loss is huge. Hence the administration should take concrete measures on a long term basis to tame the menace of recurrent floods.

Keywords: – flood forecasting, flooding, rainfall, flood management, flood

NAME: – Mahesh S Waghmare
Deptt: – Department of Engineering Sciences

RENEWABLE ENERGY SOURCES AND SMART GRIDTECHNOLOGIES
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RENEWABLE ENERGY SOURCES AND SMART GRIDTECHNOLOGIES

Smart Grid and its Challenges:-

The growing consumer demand of electric energy every day and the aging transmission and distribution power grid infrastructure in India is causing new challenges for engineers. In recent years, domestic as well as industrial consumers are using more and more computers, servers, communication equipment, process control equipment, sophisticated machinery and power electronic equipment for automation purpose and to improve efficiency of various mechanical and chemical processes. Thiselectronic equipment is called as “sensitive load” (or critical load) because it does not tolerate any voltage fluctuations, voltage sags and power failures of electric supply. In short, the consumer these daysdemands high expectations of power quality from electrical power utilities. If the electrical power is not maintained within strict power quality specifications, this sensitive electronic load equipment may get damaged or may malfunction causing huge production loss and data loss to the consumers.

At the same time, it is not possible to discard huge investments made by Governments in various countries in terms of transmission and distribution grid infrastructure. Hence, the challenge is to make the existing power grid more efficient and reliable by minimizing voltage and frequency fluctuations, providing good power quality and improving grid stability. To reduce carbon emissions due to burning of fossil fuel, government is encouraging small to mid-size installations of renewable energy sources such as solar photovoltaic (PV) systems and wind power generation systems. The nature of these renewable energy sources is that they produce intermittent power generation based on solar and wind energy availability during the day and their high penetration in grids are posing problems of voltage and frequency instability. Due to distributed nature of energy sources, fast response to the user demand needs to be achieved in more efficient manner and it is also required to balance the demand and supply patterns more closely in order to avoid power outages and voltage fluctuations at user end.

Consumer demand increase on the electrical energy sources makes it necessary to have for more efficient power generation and distribution systems instead of only increasing the installed capacity. Hence, the existing power grid needs to be converted into a “smart grid” so as to make it more intelligent, self-healing, efficient and consumer friendly so thatconsumerscan get rebate in tariff if electricity is consumed during non-peak hours.

Smart grid is nothing but transformation of existing grid into futuristic power grid which incorporates smart metering devices, advanced control techniques and Information & Communication Technologies (ICT) at transmission and distribution levels in order to supply electricity in a more user-friendly way. Few important characteristics of smart grid are user friendliness, self-sustenance, robustness in terms of its ability to accommodate various generation and storage requirements and market driven efficient operation, high power quality and reduced energy storage capacity. Hence smart grid is essential for various environmental, political, socio-economic and technical factors. Key elements of a smart grid include renewable energy sources, controllable energy storage, micro-energy management system, demand side energy management system and advanced metering including smart metering devices as shown in Fig. 1 below.

Smart grid also incorporates demand side load management which allows customers to make selection of their energy consumption requirements during a day schedule and helps utility companies to reduce their peak load demand significantly. Demand side load management allows customers to make decisions regarding their energy consumption and helps the energy providers to reduce the peak load demand and reshape the load profile. It focusses on utilizing power saving technologies, electricity tariffs, monetary incentives and government policies to mitigate peak load demand instead of increasing the installed capacity. The shape of load demand curve is changed by reducing the total load demand during the peak hours by shifting the loads to be served during more appropriate timeof the day thereby reducing the overall operational cost.

Another technique of demand side load management is the use of electric spring technology. This technology can be used for providing good power quality by stabilizing voltage and power fluctuations caused due to renewable energy generation such as Photovoltaic (PV) and wind power sources. Electric spring essentially consists of power electronic inverter which dampens the voltage fluctuations caused by intermittent renewable generation by absorbing or injecting the reactive power and distributing it to the non-critical loads which areconnected in series with the electric spring. It ensures stable voltage and power to the sensitive electronic loads.Electric spring essentially converts the non-critical, wide voltage resistive load such as heating and lighting load to a “smart load” which follows the patterns of renewable power generation and the voltage at the critical load is maintained constant. It also improves the power factor and reduces the energy storage requirements of the grid.

Future Research:

Currently extensive research is going on in this emerging area of “smart grid” in terms of development of new algorithms to make the grid more efficient and secure. Confidentiality of data is very critical for reliable and smooth operation of smart grid. Also, large amount of data gets generated within the grid, hence data analysis and data mining techniques are used for processing the data efficiently and take smart / intelligent decisions regarding demand side load management by training the grid using fuzzy logic and artificial neural network techniques. Consumer load patterns can be analyzed and decisions can be taken regarding intelligent switching of the loads and/or use of electric spring technology so as to reduce the peak demand on the grid and energy storage requirements.

Prof. Ravindra Joshi
Associate Professor, Dept. of Engineering Sciences
International Institute of Information Technology (I2IT)
P-14 Rajiv Gandhi Infotech Park, Pune-411057
Email: ravindraj@isquareit.edu.in
Mobile: 9822021594

The Struggle for Virtue

The word STRUGGLE has come to have a negative meaning. But according to me every struggle is victory.  It’s never easy to be great. If it were, everything would be amazing and easy and eventually have no worth there is no shortcut to achievement.

To be able to stay the course and be committed and thrive on challenges requires more than intellect or academic achievements. It requires the right attitude. This often heeds back to childhood and how the environment in which we rear children has been. Do we raise them with optimism and teach them not to fear? Do we communicate to our children that every opportunity has a difficulty and that every difficulty is an opportunity or do we rush and catch them before they can fall and learn from their mistakes? Are we not letting our children develop their emotional and intellectual strength because we do not let them ever stumble? Are we trying to make today so easy that their tomorrow will be difficult for them?

Our children need to know that tough times are inevitable. It is natural for us to protect our children but sometimes it has the negative impact. Children cannot fend for themselves if we pave their path and it too easy for them. We will also rob them of the feeling of achievement that follows struggle. We should not keep them away from struggle. When children know that every day is an adventure and they only have to know how to correct their course and steer themselves in the right direction, they will pick themselves up and take the right steps.

I2ITis the institute where faculty get all required support to nurture students beyond syllabus.Together with I2IT, I wish that every student would learn the skill to tackle every failure to get all the success.

At the end I would like to say that without painful struggle there wouldn’t beMr.Sachin Tendulkarcalled as a “God of Cricket”, Dr. Abdul Kalam called as a “Missile Man” and Mr.Amitabh Bachchan called as a “Star of Millennium”.

The author of this blog article is Dipak Raut, Assistant Professor, Department of Electronics and Telecommunication, Hope Foundation’s International Institute of Information Technology, (I²IT), Pune (www.isquareit.edu.in) (dipakr@isquareit.edu.in)

Life Without Electricity – Can you imagine?

Electricity is an integral part of the modern lifestyle.  We are completely dependent on uninterrupted power supply to power our gadgets, appliances, healthcare, education, you name it and that requires electricity. The basic requirements for human survival used to be food, clothing and shelter but today electricity and internet have been added to that survival list. Our everyday life is powered by electricity. Imagine the few hours that the local power grid has a shut down – the effect is restlessness, stress, anxiety, worry and the moment the power is restored the first sound is  “Ah”, a big sigh of relief.

From a surgeon in the operation theatre, to an engineer in a factory, to a motor-mechanic in the garage, to an officer in a company, to passengers ona railway platform, all are enjoying the interrupted service rendered by electricity. Modern transportation nowadays is moving towards electrical energy. All these just imply that the demand for electrical energy is increasing but there is gap between supply and demand. While the demand is high,and supply is less; there will exist problems leading to all forms of imbalance.If we want to bridge this gap,we need to increase generationof electricity which requires lot of capital investment and could possibly have negative environmental impact.

Though extensive research is being conducted in the fields of alternative energy sources, we are largely dependent on natural resources to cater to the existing demand.  It is not difficult to comprehend that the natural resources are limited, and we will run out of them eventually and it is does not require one to be a rocket scientist to realize that we need to conserve our resources; and we need to do it NOW. We should all ensure that we use our resources wisely and stop all forms of wastages. If we become careless about that, then we are most definitely looking at regular and prolonged load-shedding. Leaving the lights and fans on during the day will only keep us in the dark at nights. It’s time we all cared about the environment.

Recently our Prime Minister Narendra Modi called out to the entire nation to switch off lights for nine minutes on April 5,2020.  Though the essential services like public utilities, municipal services, offices, police stations, manufacturing facilities were asked to continue, approximately, 15-16 GW energy demand reduced in a span of 9 minutes.A small change can make big difference. Individually, we cannot generate electricity, but individually, we can save it.

The author of this blog article is Amit Kasar, Assistant Professor,Department of Engineering Sciences, Hope Foundation’s International Institute of Information Technology, (I²IT), Pune (www.isquareit.edu.in) (amitk@isquareit.edu.in)

Amit Kasar
Engineering Science Department

Yoga Enhances Professional Performance – Can It?

Yoga is a science and a discipline that has been handed down to us by seers and mystics who developed techniques to enhance our physical and mental agility.  It is said that the practice of Yoga brings flexibility to the spine and joints, keeps the muscles of the body pliable and youthful, increases circulation of blood and strengthens our internal organs; Yoga is all this and more. Yoga improves the power of concentration, cures constipation, relieves stomach disorders, improves coordination of muscles and reduces body fat, strengthens the mind-body connection, calms and relaxes the mind, enhances self-confidence, strengthens self-discipline and self-resolve, reduces stress and increases vitality and energy throughout the body – in fact it can be presumed that NO other form of known exercise can provide all these benefits at one go.  Hence, it would appear that yoga has extensive benefits and can help us to be more balanced, relaxed, focused, efficient and effective – professionally and personally.

In today’s competitive professional world physical fitness can be directly proportional to an individual’s and team’s performances.  Technological developments have reduced effort which has impacted people’s physical and mental ability.   People are willing to invest in developing professional skills towards advancing one’s career but it is crucial that one needs to support that will a healthy body that is flexible, strong and controlled.  In ability to move one’s body with dexterity performances will be lacklustre. Similarly, if one is not able to maintain endurance or stamina for a considerable duration of time, the performance will be diminished. In order to be successful, it is also necessary that a person stays focussed and concentrate with confidence on the task without distraction. Dealing with distractions, adversity and stress is an important component of everybody’s life. So, how can yoga assist in strengthening the mind and body of a person and help him/her perform his/her best?

Yoga is the application of physical postures, control of breath, purification and relaxation of mind body and spiritual principles aimed at bringing greater unity and balance to the mind and body. Yoga teaches a person how to link the mind and body and to come into the present. The breathing techniques in pranayama helps a person to focus on breath, calm the mind and build concentration ability.

Yoga asanas also help to develop the control and concentration of the mind. Being able to hold a posture with steadiness, relaxation and comfort requires that a person is able to focus their mind for an extended period of time. This leads to developing strength and concentration in mind / body and is beneficial to be alert and fit even in competitive scenarios.

Asanas also help to create harmony and balance between the mind and body and help to achieve a healthy body and stable mind, It is all about controlling the mind through physical discipline. Asana aid the efficient functioning of internal organs this leads to an overall positive effect on our body. Yoga Asanas are designed to keep the proper curvature of the spine and to increase its flexibility, develop the function of the cerebellum, the brain centre that controls the body when in motion, improve muscle coordination which improves the grace and fluidity.

YOGA IS FOR EVERYONE. Yoga works on strength, flexibility, balance, agility, endurance, core, and overall strength, among other things. Anybody can benefit hugely by adding yoga to his / her daily regimen. Here’s how Yoga can enhance your life…

Strength: consistently holding up your own body weight will give you more strength than lifting weights

Flexibility: Regular practice of yoga increases flexibility and ease of movement, therefore increasing range of motion. In particular, athletes in sports that require swinging action (tennis, golf, etc.) can benefit greatly. Flexibility in general also helps to prevent injury.

Balance: yoga improves overall balance in everything you do, preventing falls and injury.  When you learn how to be soft and go with the flow, you can easily bend more and are less likely to break or fall over.

Endurance: yoga gives you the endurance. When you learn to tune into your body and mind, any profession can be a form of meditation. Yoga teaches how to pace yourself, slow and steady, for the long haul.

Core: Every asana and pranayama in yoga works on your core strength. Strong core is essential for a healthy back and a healthy body.

Stability: Yoga helps strengthen and stabilize the little muscles that other forms of  physical workouts miss and are important in protecting your joints and spine.

Recovery: Yoga also helps bounce back after injuries  or ailments by tuning into your body and nurturing it with the care it wants and needs.

Most importantly, yoga changes the way you breathe, walk, think and approach everything in life: Your nimbleness with help you build confidence, help you perform better in a professional world and thereby make you successful. Your body will work in tandem with your mind, increasing your flexibility and performance all around.

To all the youngsters, I say, now is the time to set aside just 30 minutes a day and indulge in this ancient form of exercise that can have life-altering benefits for the rest of your lives!

The author of this blog article is Madhuri Reddy, Assistant Professor,Department of Engineering Sciences, International Institute of Information Technology, (I²IT), Pune (www.isquareit.edu.in) (madhurir@isquareit.edu.in)

 

Space Weather & Solar Cycle

January 22, 2020

Space weather which is governed by solar activities is the key cause of Sun-Earth interaction system. The Sun-Earth interaction significantly affects the magnetosphere- ionosphere- thermosphere system leading to diverse physical phenomena. The earth’s ionosphere is highly affected with the space weather events such as Coronal mass ejections, geomagnetic storms, solar winds and solar flares. The earth’s ionospheric parameters such as electron density, total electron content (TEC), electron and ion temperature behaves in a varied fashion to the incoming solar flux, electrodynamic drift, which makes its prediction very complicated. These parameters are found to be varying with local time, season, latitude, longitude, solar activity and with the conditions on sun and earth’s magnetic field.

Recent increase in solar activities has resulted in an increased concern of the space weather community. These solar activities can lead to the major catastrophic events. It has been proven that every 11 years or so, the solar activities reaches to a peak; this phenomenon is referred to as solar cycle. And peak observed during these solar cycles is termed as ‘Solar Maximum’. The solar maximum can extend to several years either side of the actual peak and the Earth gets subjected to by intense space weather. When these solar storms released due to severe solar activities are punched on to Earth, it may lead to various exceptional activities as well as major disasters leaving Earth out of electric power for years to come.

Solar Activities

Solar activities refer to any natural phenomenon happening on or in the Sun. These activities may be classified into:

“Solar flares are abrupt bursts in the concentration of solar emission.”

“The solar wind is composed of particles charged with very high energy that are radiated from the sun.”

“A Coronal Mass Ejection (CME) is an immense explosion of solar wind into space.”

“Sunspots are momentary phenomenon on the photosphere of the Sun that appears as dark spots contrast to neighbouring regions.”

“Solar Cycle is a period of 11 years or so where the sunspot number reaches to the peak and solar activities increases.”

“Space Weather are the fluid environmental conditions of space, especially near- Earth Space or the space from the Sun’s atmosphere to the Earth’s atmosphere.”

“A Geomagnetic Storm is an impermanent commotion of the Earth’s magnetosphere caused by the turbulence in space weather.” (Information source: Helios, Goddard Space Flight Centre web link, NASA)

Solar Flares

An abrupt, rapid and severe variation in brightness is termed as a ‘Flare’. When the magnetic energy which has built up in the solar surface is abruptly released, a solar flare takes place. Due to this sudden eruption, radiation is produced across almost the whole electromagnetic spectrum from long wavelength to short wavelength end. The quantity of energy erupted during the emission of solar flares is equivalent to millions of 100 megaton hydrogen bombs bombarding at the same instance. On 1st September 1859, first solar flare was recorded in astronomical records. And the scientists who viewed the large solar flare, separately experimenting were Richard C. Carrington and Richard Hodgson.

Due to this eruption of the magnetic energy, particles including heavy nuclei, protons and electrons are excited and accelerated in the solar environment. The amount of energy observed during mission of a flare is generally on the order of 1027 ergs/sec. And large flares can release energy up to 1032 ergs/sec. This energy released is 10 million times greater than the energy evolved from a volcanic eruption. And on the counterpart, it is less than 1/10th of total amount of energy emitted by the Sun per second.

A solar flare consists of typically three stages. First is the precursor stage, where magnetic energy release is triggered. Soft X-ray emission is observed during this stage. In the second or impulsive stage, electrons and protons are accelerated to energies beyond 1 MeV. During this stage, radio waves, gamma rays and hard X-rays are released. The steady build up and perish of soft X-rays can be observed in the final stage named as decay stage. The existences of these stages can be as tiny as a few seconds or as extensive as an hour.

The frequency of occurrence of these solar flares coincides with the solar cycle of 11 years. During solar minimum, dynamic regions are small and rare, thus the minority solar flares are identified. As the sun reaches its solar maximum, an increase in rate of eruption of solar flares is observed due to increase in the number of active regions on the solar atmosphere. This time sun will reach its peak early 2014. (Information source: flares, Goddard Space Flight Centre web link, NASA)

The author of this blog article is Dr. Rajesh V Chowdhary, Associate Professor, Department of Electronics & Telecommunication, International Institute of Information Technology, (I²IT), Pune (www.isquareit.edu.in) (rajeshv@isquareit.edu.in)

GPS Datasets for Space Research

January 22, 2020

Many Space agencies across the globe have launched satellites in particular to observe and understand the changes happening on the surface of the sun. Many instruments specifically for measuring various parameters have been orbited through these space agencies. To understand the dynamics of Sun and the related activities and to derive the affects of these activities on our daily life is the main goal of research carried out by many space agencies & their mission. NASA has dedicated a centre named Space Weather Prediction Centre (SWPC) for maintaining a real time data centre for measuring certain parameters and predicting the occurrence of extreme events. A database of real time monitoring is being updated on their website for every 15minutes. A few agencies have dedicated their work to examine the effect of these solar activities on ‘Interplanetary Magnetic Field’ (IMF) and Geomagnetism of Earth.

Similarly, the Air Force Research Laboratory of USA has established Scintillation Network and Decision Aid (SCINDA), as a set-up of ground based stations that monitor trans-ionospheric signals at the UHF and L Band frequencies. The main purpose of SCINDA is to serve as regional specification and short term forecasts of scintillation occurring onto UHF and L Band frequencies i.e., especially on communication and navigation signals. These scintillations onto signals are caused due to irregular distribution of electron density across the equatorial ionosphere region.

Image Courtesy :  K Groves

The SCINDA station gives information of two eminent parameters namely, S4 (Scintillation Index) and TEC (Total Electron Content), which are the measures of how much signal has undergone modulation during transverse and total number of electrons present in a 1-m2 cross-sectional area between satellite and station respectively. S4 is indicated by values ranging from 0 to 1, where ‘0’ represents no modulation in the signal and ‘1’ being 100% modulated signal. ‘Scintillation’ word is characteristically referred to quick amplitude and phase variations in a received electromagnetic wave. The cause may be diffractive when electromagnetic waves are spread in an asymmetrical medium composed of several little changes in the refractive index. The variations in the intensity of the signal are deliberated by the scintillation intensity index S4. Due to solar activities it is obvious that our ionosphere will expand and become more ionized. Thus the solar activity occurrences and evidences can be correlated with SCINDA network data.  Thus severe to extreme events impacts on to TEC and S4 can be realized using these stations data. Also, the diurnal, seasonal and annual variations of TEC can be studied for a specific geographic location by post processing SCINDA data.

GPS datasets can also be freely accessed at International GNSS Service Network
https://www.igscb.org/igs-stations

Image Courtesy : IGS

The author of this blog article is Dr. Rajesh V Chowdhary, Associate Professor, Department of Electronics & Telecommunication, International Institute of Information Technology, (I²IT), Pune (www.isquareit.edu.in) (rajeshv@isquareit.edu.in)

 

Selection of Sorting Method in Computer Science

Sorting is one of the major problems in Computer Science and Engineering. One needs to sort data in an ascending or a descending order based on problem statement. Efficient sorting is required to optimize the performance of other algorithms such as searching and merging. There are two types of sorting methods viz. Comparison Based Sorting and Non-comparison Based Sorting. In Comparison Based Sorting methods, elements are compared with each other to get the sorted order. In Non-comparison Based Sorting methods, elements are not compared with each other to get sorted order. Bubble Sort, Insertion Sort, Selection Sort, Merge Sort, Quick Sort, Heap Sort, and Shell Sort are examples of Comparison Based Sorting methods whereas Radix Sort, Count Sort, and Bucket Sort are examples of Non-comparison Based Sorting methods.

Worst case time complexity of Bubble Sort is O (n2), where n indicates the number of elements to be sorted. It is applicable to small size data and usually is not used to solve problems in real-world applications. The best case and worst case time complexities of Insertion Sort are Ω (n) and O (n2) respectively.  These are used in situations when the data to be sorted is small in size and is almost in a sorted order. The best case and worst case time complexities of Selection Sort are Ω (n2) and O (n2) respectively. These too are used when the data size is small. The space complexity of all the above sorting methods is equal to O (1), as these methods don’t require additional memory to get sorted order data. One can choose the above sorting methods when memory requirement is very high.

Merge Sort, Quick Sort, and Heap Sort are efficient sorting methods wherein time complexity is less. Among these sorting methods, Quick Sort is the fastest sorting method but its worst case time complexity is O (n2). Merge Sort and Heap Sort give O (nlogn) time complexity in all cases, i.e., best case, average case, and worst case. Quick Sort is preferred over Merge and Heap Sort if the researcher or developer is confident about balanced partitioning of the data.

Merge Sort is applicable in situations, when data size is very large and is unable to fit in a computer’s main memory like RAM although its space complexity is O (n). If there is a high requirement of memory and one wants to find the smallest or the largest element quickly, Heap Sort is preferred because its space complexity is O (1).

Radix Sort or Bucket Sort is specially used to sort out fixed size integers, fixed size strings and floating points of certain range and leads to worst case time complexity of O (d*(n+b)), where d is number of digits required to represent maximum number from the list, n indicates number of elements to be sorted and b indicates number of buckets required to sort out elements. For integers b=10, as there are 10 digits and for strings b=26, as there are 26 alphabets.

Counting Sort is one of the non-comparison based sorting methods, which runs in linear time, i.e., O (n+k), where n shows number of elements to be sorted and k is the maximum element. It is used when the range of the values is small and the list contains duplicate entries of the elements.

The author of this article is Prof. Ajitkumar Shitole with the Department of Computer Engineering at International Institute of Information Technology, I²IT, Pune

Know What Customers Think?

e-commerce is transforming rapidly and with many new technological advancements in the 21st century, the world is going crazy with online shopping. Customers check product availability across various e-commerce stores. Details like product specification star ratings, reviews to choose the right product, etc are all available just a click away.  Similarly, vendors are vigilant of their customers’ likings.

Though buying a product online has become easier, it is not yet possible to conduct a detailed manual analysis of all the reviews to discern feature-specific opinions. Presently, in many cases, opinion analysis is done only for the overall reviews and we cannot get the feature specific opinions of the product.  So, there is a need to analyze the opinions specified for the different aspects of a product, which can be done by using an ‘Aspect Specific Opinion Analysis’. This analysis is carried out in two steps:

  • Aspect Extraction
  • Sentiment Classification for that Aspect

Aspect Specific Opinion Analysis is done using recent technologies such as Machine Learning and Natural Language Processing (NLP).  Many a times NLP is used to extract features and a Machine Learning Algorithm is trained to predict aspect category.

Applications of aspect specific opinion analysis:

 

For example, let us consider Mobile Phone Reviews.  Major aspect categories can be processor, RAM, battery backup, camera, picture quality, color, screen size, etc.  The desired aspect is extracted from a review and then the sentiment about it is determined.

Approaches for aspect extraction:

  1. Frequency based approach: Frequent noun and noun-noun terms are extracted to predict the aspect. These are selected based on frequency/occurrence count.
  2. Syntax based approach: Candidate features to predict aspect category are selected based on POS tags or some grammatical rules which show the relationship between words in a sentence. So here we need to study different NLP rules which show relationships between words in a sentence. Then use those applicable rules to extract features to predict aspect category.
  3. Unsupervised approach: Clustering techniques can be used to group terms which reflect the same aspect.
  4. Hybrid approach: It can be a combination of many approaches such as, frequency, syntax, supervised, unsupervised.

The above listed approaches work on terms specified in the review. But the same aspect may be represented by using multiple terms. So, there is a need to think about the semantic approaches that will consider rational knowledge while predicting the aspects. One of the semantic solutions for the aspect extraction problem is ontology. The level one nodes in ontology represent aspects, and the following nodes represent opinion terms related to those aspects. As per the applications, depth of the ontology can be decided. Ontologies represent the knowledge of a domain and can be the best semantic solution.

Challenges:

The aspects to extract, may be explicit or implicit.

“The cell phone is overpriced” – The aspect, ‘price’ is specified explicitly.

“It is not affordable”- ‘Price’ is the implicit aspect that is represented by the word ‘affordable’.

The challenge is to identify the implicit aspects.

The another issue is to extract aspects from a sentence containing multiple aspects.

“It is overpriced but the picture quality is good”

In this review sentence, one aspect is, ‘price’ (explicit) and another is ‘camera quality’ (implicit).

The complexity of language and choice of words, make NLP that more challenging and exciting.  Currently the areas that are open for research aspect-specific opinion mining are:

  • Finding implicit aspects from reviews.
  • Extract aspects from sentences containing multiple aspects.
  • Semantic strategy for the aspect class prediction.
  • Unbalanced data problems.
  • Negation handling

The author of this article is Prof. Bhavana Kanawade with the Department of Information Technology at International Institute of Information Technology, I²IT, Pune.