Conventional vs.

Tactile computing,Molecular and Biological computing

Harish Kr. (1BI13LVS04)M.Tech (VLSI D & ES)

2

Outline

Conventional Computers Problems Tactile Computing Examples Biomolecular Computing DNA-an overview Drawbacks

Conventional Computers

Conventional computers are machines that follow a well described set of instructions to process data.

Basically, a set of instructions is read into the machine and it works sequentially in an ordered way to execute a task.

often referred to as Von Neumann computers or classical machines.

major components are memory, processing, and bandwidth.

3

Continued…..

Can be thought of as structurally programmable machines. This means that the program controls the behavior of the machine.

A compiler translates the input code into machine language that is expressed in terms of the states of simple switching devices and their connections.

The machine computes symbolically and the result depends to some extent upon the human input.

Well suited to computing, communication, and data manipulation.

4

Problems

pattern recognition Specifically, it is very difficult to program a classical

computer to recognize a complicated molecule or distinguish between different microorganisms.

In the chemical and biological world pattern recognition is highly efficient and readily accomplished.

For example, the immune system in the human body.

This behavior is an example of a different type of computing.

5

Tactile Computing

These machines are not structurally programmable. In Biomolecular computing, pattern processing is physical

and dynamic as opposed to the symbolic and passive processing in a conventional machine.

Programming depends upon evolution by variation and selection.

A tactile processor can be thought of as a computer driven by enzymes; the inputs are converted into molecular shapes that the enzymes(scans the molecular objects within its environment) can recognize.

Recognition is thus a tactile procedure.

6

Examples1) An example of tactile computer- A variety of bacteria bred to dissolve oil spills. the bacteria would be “programmed” by altering its DNA. the unique and powerful information processing capabilities

of life, pattern and object recognition, self-organization and learning, and effective use of parallelism are harnessed.

2) sensing bioagents or toxins. Molecules can be used to perform complicated pattern

recognition of dangerous toxins released into the air or water. Even Very dilute amounts can be identified readily. Can be used to fight terrorist bioattacks, or chemical warfare.

7

Biomolecular Computing

The “program” is in the molecule itself; the computation occurs by the recognition of one molecule by an enzyme and their subsequent chemical reaction.

Biological systems are a special case of molecular computing(broader context).

8

key advantages of molecular materials Size: on average they are about 4 nm. These device dimensions

are about two orders of magnitude smaller than that which can be obtained using SiCMOStechnology.

Three-dimensional structures: In contrast, in Si based technology, much fabrication effort and cost is required to produce three-dimensional geometries.

High packing density: the combined features of small size and three-dimensionality make very high packing densities possible. It is estimated that the packing density can be increased by 6–9 orders of magnitude over CMOS.

Bistability and nonlinearity: bistability and nonlinearity can be utilized to perform switching functions. Both of these properties are commonly available in molecules.

Anisotropy: the electronic and optical properties of a molecule are inherent in the molecular structure instead of being fabricated by the processing technologies as in CMOS.

9

Continued…..

Upward construction: organic synthesis enables growth of microstructures from the small upward. In standard CMOS, device and circuit functionality is sculpted from a relatively large piece of material.

Self-organization: self-organization, self-synthesis, and redundancy factors well known in organic and biological molecules that could potentially be applied to molecular electronic devices.

Low power dissipation: Estimates are that the total power requirements for molecular switches will be about five orders of magnitude lower than for CMOS switches.

Molecular engineering: it is possible that molecules can be tailored or engineered(can be selectively grown and made to inherently possess desired qualities to perform a task.) to perform specific tasks or have specific properties.

The above features of molecules also apply to biomolecules.10

DNA-an overview The entire genetic code for humans is contained in the

nucleus of most cells. The DNA code consists of over three billion nucleotide

pairs and fits into a few double helices about 3.4 nm in width and measuring micrometers in length.

11

Researchers are developing what are called applets for biological systems.

These applets enable the system to respond to an external event, “program” a cell to produce a desired chemical or enzyme, or enable a cell to identify a reagent.

Some potential applications of biological applets: In gene therapy for treating diseases such as hemophilia,

anemia, etc. in the treatment of diabetes( A genetic applet can be

used that senses the glucose level in the blood and another applet can then direct the production and release of insulin if needed.).

12

DNA molecules are composed of four basic nucleic acids called

adenine (A), guanine (G), cytosine (C) and thymine (T).

A and T, and C and G naturally bond together to form pairs.

13

Computation with DNA To compute with DNA there are three basic steps.

encoding that maps the problem onto DNA strands,

basic processing using a chemical process called hybridization that connects two complementary DNA strands into a double strand,

and outputting the results. Programming DNA involves the usage of DNA tiles.

These tiles consist of multiple strands of DNA knotted together.

The ends of each tile are created such that the tile will recognize and attach to other pre-designed tiles to make self-assembled structures.

These tiles can be used to add or multiply numbers 14

Molecules can also be used to build devices that mimic CMOS functionality.

Molecular diodes and other quantum based devices have been designed.

The primary components of these molecular structures are conducting groups called polyphenylenes and insulating groups called aliphatic molecules.

By arranging these molecules in various orders similar device action to that found in semiconductors can be attained.

These structures can be combined to make various logic gates such as NOR and NAND gates.

15

Drawbacks

These are basically related to the difficulty encountered in regulating or controlling the basic chemistry.

Reliability means the degree of confidence in correctly solving a problem.

Efficiency is related to the effective manipulation of the molecules used to perform the computation.

Scalability is the successful reproduction of the desired event many times.

16

Thank you !