Bootstrapping Computing Linguistics Biology Electronics

In computers, this term refers to any process where a simple system activates a more complicated system. It is the problem of starting a certain system without the system already functioning. It seems just as impossible as "pulling oneself up by the bootstraps" which Baron Münchhausen, according to stories, could do. However, solutions, accordingly called bootstrapping, exist; they are processes whereby a complex system emerges by starting simply and, bit by bit, developing more complex capabilities on top of the simpler ones.

1 Computing

Bootstrapping is generally a longer term for booting, or the process of starting up any computer. "Bootstrap" most commonly refers to the program that actually begins the initialization of the computers operating system, like GRUB, lilo or ntldr.

Bootstrapping can also refer to the development of successively more complex programming environments. The simplest environment will be, perhaps, a very basic text editor (e.g. ed) and an assembler program. Using these tools, one can write a more complex text editor, and a simple compiler for a higher-level language. and so on, until one can have a graphical IDE and an extremely high-level programming language.

Methods for distributing compilers in source code include providing a portable bytecode version of the compiler, so as to bootstrap the process of compiling the compiler with itself.

2 Linguistics

Syntactic bootstrapping is the idea that children use syntactic knowledge they have developed to help learn what words mean -- semantics builds on top of syntax.

3 Biology

The idea of bootstrapping is significant in a number of fields in the biological sciencesBiology studies the variety of life clockwise from top-left E. coli tree fern, gazelle, Goliath beetle Biology is the science of life. It is concerned with the characteristics and behaviors of organisms, how species and individuals come into existence, an. The process by which a fertilised ovum develops into an embryotadpole) of the wrinkled frog Rana rugosa . An embryo is an animal or a plant in its earliest stage of development. Plants In botany, a plant embryo is part of a seed, consisting of precursor tissues for the leaves, stem (see hypocotyl , and root (see rad, particularly the way in which the nuclear genomeGenome is also a popular science book by Matt Ridley. In biology, the genome of an organism is a complete DNA sequence of one set of chromosomes; for example, one of the two sets that a diploid individual carries in every somatic cell. When people say tha is expressed differently in its various cells as these differentiate, is one example of bootstrapping. The evolution of progressively better adapted organsIn biology, an organ is a group of tissues which perform some function. Common animal organs include the heart, lungs, brain, eye, stomach, spleen, pancreas, kidneys, liver, intestines, skin, uterus, bladder, bone, etc. Common plant organs include the sta through natural selectionAlternative meaning Natural Selection (computer game . Natural selection is the primary mechanism within the scientific theory of evolution, i. it alters the frequency of alleles within a population. It was first proposed as the main mechanism of evolutio in a lineage of organismIn biology and ecology, an organism is a living being. The origin of life and the relationships between its major lineages are controversial. Two main grades may be distinguished, the prokaryotes and eukaryotes. The prokaryotes are generally considered tos is another. Some biologists, including Graham Cairns-Smith , believe that the origin of lifeThis article focuses on modern scientific research on the origin of life. For alternate uses, see origin of life (disambiguation). Research into the origin of life is a limited field of research despite its profound impact on biology and human understandi itself may have been a bootstrap process as one or more systems of biological information storage formed the foundation for successor systems that ultimately supplanted them culminating in the emergence of our current DNADeoxyribonucleic acid DNA is a nucleic acid which carries genetic instructions for the biological development of all cellular forms of life and many viruses. DNA is sometimes referred to as the molecule of heredity as it is inherited and used to propagate-based system. For more details see the articles on embryology, ontogeny and phylogeny and RNA World.

4 Electronics

The term bootstrap has a number of meanings in electronics. In classical analog designs, a bootstrap circuit is an arrangement of components used to boost the input impedance of a circuit by using a small amount of positive feedback. This was often necessary in the early days of bipolar transistors, which inherently have quite a low input impedance. The need for such arrangements has largely been alleviated by the use of modern field effect transistor designs, except when ultra-high input impedances are required.

Another meaning is in connection with the booting process of a computer or other complex system, where the underlying electronics must arrange for the orderly startup of the actual CPU and related electronics components. This is done long before the CPU is in a state where it can begin to execute software. Nowadays the bootstrap is coordinated by special integrated circuits that monitor the raw power supply and provide the relevant signals to enable the CPU and other chips accordingly.

In a typical car alternator, a DC field current is required before the device can produce any output. Once running, a small portion of the output is fed back to keep the field alive — this can be seen as a form of bootstrapping. The initial priming current is usually obtained from the vehicle's battery — if the battery is totally flat the alternator won't produce any output voltage to recharge it even if the engine is started (by push starting for example) since it will be unable to bootstrap itself. However, in practice, a battery will usually have enough residual charge to avoid this.

5 Statistics

In statistics bootstrapping is a method for estimating the sampling distribution of an estimator by resampling with replacement from the original sample.

Bootstrap technique was invented by Bradley Efron (1979, 1981, 1982) and further developed by Efron and Tibshirani (1993). "Bootstrap" means that one available sample gives rise to many others by resampling (a concept reminiscent of pulling yourself up by your own bootstrap). While the original objective of cross-validation is to verify replicability of results and that of jackknife is to detect outliers, Efron (1981, 1982) developed bootstrap with inferential purposes.

In bootstrap, the original sample could be duplicated as many times as the computing resources allow, and then this expanded sample is treated as a virtual population. Then samples are drawn from this population to verify the estimators. Obviously the "source" for resampling in bootstrap could be much larger than that in the other two. In addition, unlike cross validation and jackknife, the bootstrap employs sampling with replacement. Indeed, sampling with replacement in a bootstrap is more accurate than sampling without replacement in terms of simulating chance. Further, in cross-validation and Jackknife, the n in the sub-sample is smaller than that in the original sample, but in bootstrap every resample has the same number of observations as the original sample. Thus, the bootstrap method has the advantage of modeling the impacts of the actual sample size (Fan & Wang, 1996).

6 Finance

In finance, bootstrapping refers to the procedure used to calculate the zero coupon yield curve, solving for the maturities where no instruments are available. The method uses interpolation to complete the yield curve, using available zero coupon securities with varying maturities.

7 Resources

Diaconis, P. & Efron, B. (1983). Computer-intensive methods in statistics. Scientific American, May, 116-130.
Edgington, E. S.(1995). Randomization tests. New York: M. Dekker.
Efron, B. (1979). Bootstrap methods: Another look at the jackknife. The Annals of Statistics, 7, 1-26.
Efron, B. (1981). Nonparametric estimates of standard error: The jackknife, the bootstrap and other methods. Biometrika, 68, 589-599.
Efron, B. (1982). The jackknife, the bootstrap, and other resampling plans. Society of Industrial and Applied Mathematics CBMS-NSF Monographs, 38.
Efron, B., & Tibshirani, R. J. (1993). An introduction to the bootstrap. New York: Chapman & Hall.

8 External link

Yu, Chong Ho (2003): Resampling methods: concepts, applications, and justification. Practical Assessment, Research & Evaluation, 8(19).

<Hide>

Home > Bootstrapping