Hysteresis - Sri Lanka

The current cultural scenario can be seen as a “hysteresis”. If you refer any dictionary for “hysteresis”, they all will point you to the common meaning known as “deficiency” or “lagging behind”. But I like the phenomena called “hysteresis” (the history of the system has something interesting to cause the present situation) more in using it to describe the present day which is obviously not the initial state of Sri Lanka.

Hysteresis is observed when a system is induced with some property like magnetism. As we all have once done the experiment on temporary magnets created using a conducting coil; perhaps you may remember that the magnetic property remained in the “nut” or the “nail” even after the electric current was cut off. This residual magnetic field is a “hysteresis”. In general, before the hysteresis, the system experiences a dramatic shift in its field (magnetic field when we consider this context); this shift is HUGE compared to the initial external field.

The simple fact about this is that you don’t need a huge energy to produce a mammoth field: the tiny magnetic droplets in the nut or nail (the material used for the induction) will align themselves in order to give you a resulting saturated state of huge magnitude. And if the material used for the induction, is hard magnetic material then, the residual magnetic field will be quite significant.

Over the last many years we, Sri Lankans, have been experiencing cultural hysteresis and now also we are proudly continuing it- because we are like hard magnetic materials. I believe that the hysteresis caused by the British invasion is the building block of present day Sri Lanka; nobody can deny it. We are nothing but the small dots trying to make our way, arrange our “spin” according to the British. Therefore, we cannot argue that we are building the proud Sri Lanka which is described in the tales and history books: dudes we are in a HYSTERESIS, and we cannot go back to the 0-state. 

Science and Us: in the context of Readers and Writers-I

Many of us who are learning scientific writing have so much problems regarding the word usage. The basic rule in this type of writing is, being clear, concrete and concise all the time. When we are writing a scientific article we should always focus on our audience: the readers. The readers are not always the same; they belong to different groups and their language backgrounds are vastly different. For an example, if we use "case" as in 'in this case' rather using 'in this instance' some readers might get confused; they will interpret that it is some object like a 'beer case' that we are referring to in the text. Of course in relation to the context, if the reader has read the overall text then he or she may be able to understand that idea, but we cannot let ambiguities to exist in the writing.

In this particular blog post I am more interested in discussing certain word usage in the scientific writing which I found to be more interesting to my liking but of course that interest can obviously differ from yours.

1. Using And, But to begin a sentence:
• Many of our school teachers have told that using and or but at the beginning of a sentence is not appropriate. But it is not true. And we can use two of these words at the start of a sentence preserving the integrity of the flow of our idea (see I have done that here also!). If your idea is clear to the reader then there is no worry. 

1. Above, Below:
• Well evidently these two are troublesome words in the readers point of view. It is perfectly convincing, however, in the writers point of view. But, if the writer refers to that same text after sometime then he/she will also feel difficult to grasp the idea. This difficulty causes the loss of clarity. So it is always better to use the exact figure name, heading or sub-heading, and relevant table names etc. when you are referring in the text while not using the two words- above, below- mentioned here.
  
   
2. Compare to or Compare with:
• In the text when the word compare appears I feel that it has something to do with analyzing the quality of being similar or equivalent. That idea is quite true. In fact, compare to means to represent as similar whereas compare with states examining differences and similarities. Therefore whenever compares to is used the idea is that the two parameters are similar; e.g. Kumar sangakkara's records as a batsman compares to that of Don Bradman's but to do that we should compare sanga's records with bradman's.
3. What can the word Comprise do to the text:
• I often thought that comprise is a very good word to be used in writing. But observably I was wrong. The general meaning of comprise is consist of or be made up of, but the word is also used to mean to contain, include or encompass. This multiple meanings of the word can cause ambiguities as a whole and therefore it is better to avoid the word in the writing.
4. Due to the phrase Due to:
• When I was asked to write my first paper, I used so many of "Due to"s that I now feel guilty. Well this particular "adjective modifier" must be used with caution; and this shall be related to a noun. If a sentence begins with "Due to the fact that..." then it can be either because the writer is trying to fill up the space as there is nothing more coherent argument to be said or just a cunning act to misguide the reader. But having contended that I must also claim that there are good uses of such writing as well!, nevertheless as a whole it is better not to use much of the specified phrase.
5. As:
• As we are reading and writing science, it is always observable that as is used. But when as is used to mean that or whether, it becomes confusing. Therefore it is more intriguing to use as for the sole use of as only; avoiding other uses such as to mean, because, and inasmuch as also.

This post concludes here and some more things are to be discussed in later posts.

cheers 

#SD!

Scientific Writing - The Introduction

Well, after a long time, I thought of raising my voice- Although you may not hear the voice, you can at least read the thoughts-  creating this article, is the result. During the past few months, I was struggling endlessly to write scientific articles; I couldn't still find a way to succeed; life sure is tough. But I have gathered few important facts about scientific writing.

Scientific writing is not just presenting facts, it is about telling your story; the one you have unveiled in the research. Generally you have to tell the story systematically so that your reader is capable of grasping the main idea of the research. It is not to be forgotten that there are various readers; each and every one of them understands the story in different ways, and that is the beauty of it. For the writer however this "beauty" comes with a great pain. The writer therefore have to put the shoes of the reader and he should write so that the reader can understand what is said. One thing has to be remembered, what scientists do in researches is creating knowledge and if that knowledge can not be transferred to the common world then there is no use of doing the research. 

The scientific story starts with an "introduction"; a small briefing to the veil that is to be unveiled. In introduction, what the writers usually do is explaining the background of the study:

Lets assume that the topic of the study is "Scientific Writing", then in the introduction it is to be explained, what exactly is "Scientific Writing"; why people use it, and what kind of pros and cons are there. In many occasions the readers will find that, by reading the introduction a general picture about the whole study can be visualized, but an introduction is just a beginning; you cannot comment on the research just by reading the introduction. In an introduction, writers may explain in brief, the ongoing studies as well as the problems associated with them. 

In my brief study about the art of scientific writing, I found that the introduction is like the key to the map to the treasure of knowledge created; the knowledge which is somewhere hidden. With every word the writer is telling us what is the destination and its significance. It is the key to the map. If someone could not put the right key there at the beginning, nobody is going to find that hidden treasure- the irony is that the scientists want that treasure to be found- but it will remain hidden. 

බල්ලෝ බුරති ...!

two people make two images out of this one image... that is the  relativity of knowledge.!

සිතුම් රැළි..

අහස් ගැබ වී මගේ ලෝ තලයේ..
ස්නේහයක් පුද,
ලෝකයට රහසේ.....

සැඟව යනු කෙළෙසේ...//

ඉමක් නොපෙනෙන සිතුම් රැළි සයුරේ..
සොයා එන්නෙමි,
කෙළෙස හෝ නුඹ
ලෝකයට රහසේ...

සොයා එමි කෙළෙසේ...//

සෙනෙහසේ ක්ෂිතිජයම වී
දුර ඈත පෙනෙනා,
මා නොදන්නා ගීතය ද නුඹ
මා නොදන්නා ප්‍රේමයද නුඹ...
මගේ ලොව සරණා..
මතකයක් වී
මගේ ලොව සරණා.....//

Sensors (A & P)

hi...it has been a while that we haven't talked about our beloved topic 'remote sensing' so i thought its the time to do the otherwise.
today let us talk about sensors for a start.
in the dictionary the word 'sensor' is defined as a device which detects or measures a physical property.

well of course it is true that in the journey of our lives from birth to death we use so many sensors in order to interact with the world.in my case the world is what i have sensed through my sensors.

eyes,ears,skin,tongue,nose they all acted as sensors (but not all as remote sensors). in remote sensing we consider about the sensors which don't require a physical contact with the object being measured or detected.

the most significant sensor for me is the "EYE" it is the fundamental remote sensor of the human body.
just take a look at the human eye .

similar kind of thing happens with the sensor of a remote sensing platform.now for an eye to get info about an object light must enter through the cornea.but we all know that the source of the light which enters the eye reflecting off an object is not the eye itself, no wonder why we dont see people with flash bulb eyes lol... so human eye is what we call a "passive sensor"

passive sensors need a source to illuminate the object being observed and that source is not embedded to the sensor.(as in Landsat )

















so the active sensors are the opposite of the passive ones they have got their own source of electro-magnetic radiation emitter.(as in SONAR,LIDAR)

RS-from the Space to the "over head"

Hi, it has been a wonderful experience so far to explore some of the interesting topics in the field of remote sensing.As a matter of fact today we would jump from Satellite to the Aeroplane in order to grasp the techniques of RS...!

as we are well aware of the fact that the satellite imaging can be done with various objectives bearing in mind, i would like to summarise some of the characteristics or the abilities of some satellites(with common sense of course .... lol)

Ok, what is meant by the 2nd column header, it is simply an indication of the "spectral resolution" of the particular satellite-if it can grasp more and more bands and wavelengths the spectral resolution gets higher and higher..
Then in the next header it is named as "spatial resolution",well there is no need of big words to express what it means!!,we'll take an example mmm..
     take satellite sensor TM 4-5 (it belongs to the Landsat), it has a spatial resolution of 30m in first 5 bands,this means that the sensor can identify two objects as separate entities (or distinguish among each other ) only if the distance between them is greater than 30m !
of course by "repeat coverage" it means the temporal resolution, i'll give you a funny example,
            sri lankan A/L students can only sit for the A/L exam during the month of August,so the temporal resolution of A/L examination is (approximately) 365 days (1 year,if we count from the first day to the next first day), ***but any intelligent person may realise that not like the A/Ls the satellites do function on time so they would come to the top of a place on a sharp time....

if i dont say that by "orbit altitude" it means the height of the orbit of a particular satellite,this article would be incomplete.. but let us see what is meant by "swath width" >> !

as you can see the Swath width is the maximum distance that a sensor can grasp... if you took a rod with a length of (say) 1m and held it horizontally on a clear sand surface and dragged it,it would make a rectangle, 1m wide,similar story happens with the satellite sensor also.

Right, now lets step bit forward.

Satellite imaging is not the only possible method of taking images from above,there are so many other methods also, imagine somebody taking photographs from an aeroplane, let us not be so rude to imagine him falling to the earth .........lol.
yes, there is a methodology like that and it is called "Aerial Photogrammetry"..!
Not like in satellite imaging, in aerial photogrammetry the wavelength used to acquire information is in the visible wavelength region (most of the time.).
the reason why i put the term "most of the time" is that,in aerial photogrammetry we take photographs using a  metric (usually an analog) camera so the images are captured in their visible range.
here a Mosaic of overlapping photographs are used for the interpretation.

i would tell it like this way................
 this is identical to the act of "we flying over that terrain with our both eyes open" ,as you may have heard how we,humans see objects in a 3-dimensional way,you might witness that the way in which the photographs are taken is pretty much close to it.
the overlapping image part is in an orthogonal direction to the flight direction (side lap) must be around 30% of the swath width and the overlapping image part to the flight direction (forward lap) must be 60% of the same.in order to derive planimetric and topographic information......


let us talk about some more later. adios........!