What is Remote Sensing

Remote Sensing Definition

Simple definition:

Remote Sensing is the collection of information about an object without direct contact.

Wikipedia definition:

Remote sensing is the acquisition of information about an object or phenomenon without making physical contact with the object and thus in contrast to in situ observation.

Remote Sensing Applications

1. Land use mapping

2. Urban planning

3. Environmental applications

4. Global change and Meteorology

5. Hydrology and Coastal mapping

6. Forest and Agriculture applications

7. Telecommunication planning

8. Emergency and Hazards

Remote Sensing Advantages

1. Provides synoptic view (ability to see large area at the same time)

2. Reduces data acquisition time

3. Repetitive look at the same area at regular intervals for monitoring

4. Collecting data about areas that are physically inaccessible

5. Provides data in every weather and at any time of the day (though this depends on the type of RS method adopted)

Remote Sensing techniques

Passive Remote Sensing is the system which measures energy that is naturally available.

Active Eemote Sensing is the system which provides their own source energy for illumination

1. Optical technique

• Passive technique
• Camera, telescope used
• Infrared portion of electromagnetic spectrum used
• Relies on ambient light source (sunlight)
• Problems with cloud, rain, fog, snow.etc
• Only for surface (cannot penetrate vegetation, soil.etc

2. Microwave technique

• Passive technique
• Radar, radiometer used
• Microwave and Radio frequency portion of electromagnetic spectrum used
• Largely immune to cloud, smoke, precipitation

3. RADAR (RAdio Detection And Ranging)

• Active technique
• Transmites microwave (radio) signals towards scene and Recieves the portion of transmitted energy backscattered
• Observes the strength (detection) and time delay (ranging) of signal
• Operates in any time of day and through cloud cover

4. LIDAR (LIght Detection And Ranging)

• Active technique
• LASER (Light Amplification by Stimulated Emission of radiation) used
• Pulses of LASER emitted from sensor and reflected energy from target detected
• Time required for energy to reach target and return to sensor used to determine distance

Logic, is it really above all else?

Human beings are logical creatures. But are we really that logical? And is logic really that big?

Civilization is marked by logical thinking. Often, this is extended into the idea that primitive society was not so logical, as evidenced by the large amount of superstitions and irrational beliefs that can be found in almost every primitive society. But the modern society, civilized as it is, isn't free of superstitions. Can logic coexist with superstitions? If not, how can we call ourselves logical?

Then there are things a lot of people simply hold beyond logic. Love is one example. In a way, expression of love means to act irrationally. This is, of course, an oversimplification. But it makes the point. Mixing logic with love is a very complicated task, and many believe it simply isn't possible. So, it this an illustration of the limits of logic? Or is it a shortcoming of people as logical beings?

Well, that's a lot of questions. The easy answer to all of these questions is that there is no right answer. It's complicated. But this is, quite honestly, a cop out! If we claim to be rational beings, we must be able to answer these questions rationally. And "there is no right answer" isn't that.

The value and limits of logic is what I aspire to explore in this blog. I realize that anything I write will only be my opinion. No matter how much research I do on the topics I write, I will only be expressing opinions, either mine or of someone else. And you know what they say about opinions. Well, they say a lot of things about opinions. But opinions are important. They are the product of of logical thinking.

So this blog is about logic. Every aspect of life will be approached logically. And we will see how far logic can take us, and where it's limits lie, if it does indeed have its limits.

Nanotechnology

      

         Nanotechnology is one of the youngest discipline of science. Literally speaking "nano" means "a billionth of a meter", so the technique or technology employed to manipulate matter at this level is called "Nanotechnology". What a civil engineer is responsible for the building and designing of structure that is durable, comfortable and economical with construction and maintenance. The materials used in construction are concrete, steel, cables, glasses, paints etc. Materials used in construction works has properties like elasticity, density etc., which further influences life, strength and even the economy of construction. Maintenance of the structure is also serious concern for a civil engineer. Earthquakes, acid rain, chemical activity of materials in construction etc. affects the strength and durability parameters of the structure. But the structure has to withstand these all with acceptable damage(non-structural). To cope with such challenges we need to apply nanotechnology to enhance the material properties like:-

1. Concrete properties can be improved using CNT.
2. Temperature dependent properties of steel can be enhanced.
3. High strength cables are made.
4. Self-cleaning glasses are made.
5. Hydrophobic and heat insulating paints are produced.
6. Nanosensors are used for SHM. and many others.
USA has spent more than 20 billion on Nanotechnology.

Presentation on "Nanotechnology in Civil Engineering" is below:- 

Disaster Management

       

      Literally speaking natural disaster is the effect of a natural hazard (e.g., flood, tornado, hurricane, volcanic eruption, earthquake, heat wave, or landslide). Disaster management is increasingly a global enterprise for international organizations, Governmental institutions, and arguably individuals. Disasters are either caused by natural phenomena or human action. Natural disasters can be also exacerbated by human error during reaction and mitigation .Examples of natural disasters   internationally mitigated include earthquakes, volcano eruptions, severe droughts, floods, and indeed tsunamis.

           

            Disaster management is a vast domain that includes treaties, laws, policies, equipment, and training implemented by the United Nations down to community civil defense organizations. Organizations can be characterized by their roles in disaster management such as policy making, types of disasters they respond to, funding sources and benefactors, information sharing, training and preparation, response personnel and equipment, damage assessment, response and recovery, and control. Local government should provide them with economical as well as human resources. Disasters on a continuum include small-scale events localized. Small disasters are relevant, often posing unique problems, they typically are locally mitigated.

        

             Disaster management begins with preparations. Preparations range from earthquake proof building codes to public alerts. Preparations also include training. Training not only familiarizes people with disaster management duties, but also identifies where additional preparations might be needed. For disaster management training, situational awareness depicting a scenario both analog and digitally can be used to exercise participants. Analog procedures could be as simple as having participants use a map and phone to react to scripted events. Digital procedures might be as complex as simulations portraying a disaster and participant mitigation efforts distributed in real-time across dedicated communication lines.

        

          The training should reflect the real disaster were it to occur. Then only we can bail out of such devastating situation. Disaster management training is often conducted with the use of localized and distributed simulations.

Presentation on "Nanotechnology in Civil Engineering" is below:-