Diffusion index meaning in the cambridge english dictionary. Watson woodrow wilson school, princeton university, princeton, nj 08544, and national bureau of. He presents examples and studies where the theory has been applied to a wide variety of innovations, e. A type of stock measurement index used in technical analysis that is used in measuring the percentage of securities that have moved forward in their price or that show a positive movement throughout a specific time frame. Such forecasts may be made in great detail or may be very general. If you would like to help provide free books to prisoners, you can make a donation here. Examples of diffusion perfume is sprayed in one part of a room, yet soon it diffuses so that you can smell it everywhere. Diffusion indexes a barometer of the economy subject. We discuss, for example, the construction of factors used in prediction models implemented using diffusion index methodology and approaches that are useful for assessing whether there are. The approach is to construct a relatively few indexes, akin to diffusion indexes, which are weighted averages of the predictors, using an approximate dynamic. A drop of food coloring diffuses throughout the water in a glass so that, eventually, the entire glass will be colored.
In econometrics, a diffusion index also known as a dynamic factor is a series which measures the comovement of many time series. Estimation is discussed for balanced and unbalanced panels. The approach is to construct a relatively few indexes, akin to diffusion indexes, which are weighted averages of the predictors, using an approximate dynamic factor model. A diffusion index measures how many stocks are advancing within an index, typically on a daily time frame. Diffusion indexbased inflation forecasts for the euro area. Osmosis definition and examples biology online dictionary. The total index is an average of the first six subindices in the list above.
Diffusion processes in advanced technological materials. Rate of diffusion through a solution chemistry libretexts. Economic forecasting, the prediction of any of the elements of economic activity. The stream of diffusion scholarship over the past forty. The dissimilarity in the amounts of solute s, particles, or molecules between the two regions will cause them to move between the two regions. Diffusion kindle edition by smith, stan c literature. But once diffusion indexes become familiar, they make a whole lot of sense. Use features like bookmarks, note taking and highlighting while reading diffusion.
To chart a diffusion index and label it properly, you really need to understand what the numbers. Each particle in a given gas rate of diffusion through a solution chemistry libretexts. The oecd converts the indices into balances to allow crosscountry comparability. It is similar to diffusion as the movement is downhill, meaning from higher to lower concentration. In a book, the index points to the place in a text where things may be found, and may also indicate what is in the book. Diffusion index article about diffusion index by the. Diffusion kindle edition by smith, stan c download it once and read it on your kindle device, pc, phones or tablets. Diffusion indexes, rates of change, and forecasting core. Diffusion definition and examples biology online dictionary.
Graph and download economic data for chicago fed national activity index. Diffusion in functional organic chemicals, polymers, granular materials, complex oxides, metallic glasses, and quasicrystals among other advanced materials is a highly interactive. It seemed that the diffusion of gases through other glasslike materials such as some organic membranes, for example, rubber, might offer further examples of nonspecific activated diffusion. Take a look at the four examples of diffusion indexes in this post. Effect of diffusion and recombination in a solar cell 4. Economic fluctuations and growth this paper considers forecasting a single time series using more predictors than there are time series observations. Understanding diffusion of innovations 3 reinvention is a key principle in diffusion of innovations.
For example, we have found that diffusion indexes for output and employment in. The advancedecline diffusion index, also called simply diffusion index, measures the percentage of stocks with positive momentum and is used to analyze industry groups and market indexes. Stock kennedy school of government, harvard university, and national bureau of economic research, cambridge, ma 028 mark w. Diffusion indexes confuse the heck out of people the first time they see one. This second edition of a highly acclaimed text provides a clear and complete description of diffusion in fluids. Diffusion is defined as the process or state of something spreading more widely. In one published data series on that design, the diffusion index is computed from a panel. Carrier diffusion is due to the thermal energy, kt, which causes the carriers to move at random even when no field is applied. Diffusible dictionary definition diffusible defined. A diffusion index is created for each of the above questions. The book discusses the principal bonding variables and recommended procedures for diffusion bonding in vacuum. In addition to the nine questions above, each facility is asked how much they will spend on capital equipment in the next 12 months. An example of a diffusion index in the market place is the general business conditions index produced by the philadelphia fed survey. It retains the features that won praise for the first editioninformal style, emphasis on physical insight and basic concepts, and lots of simple examples.
For diffusion to occur there must be a concentration gradient. Diffusion in a gas is the random motion of particles involved in the net movement of a substance from an area of high concentration to an area of low concentration. Motivation molecular diffusion is often negligible in environmental problems exceptions. Find all the books, read about the author, and more. For example, the regional diffusion indexes pro duced by the. A small selection of book anouncements with relevance for the diffusion community can already be found on this page. The tick index is a shorterterm breadth indicator, as it measures how many stocks had an uptick versus a downtick. Diffusion beading of materials is an attempt to pool the experience in vacuum diffusion bonding accumulated by a number of mechanical engineering works, research establishments, and colleges. This random motion does not yield a net flow of carriers nor does it yield a net current in material with a uniform carrier density since any carrier which leaves a specific location is on average replace by another one.
A diffusion index measures the cumulative number of stocks that are advancing over time. Diffusion index of eight leading indicators, threesix. Short table of contents list of figures, list of tables title page table of contents cdrom help. Diffusion is the net passive movement of molecules or particles from regions of higher to regions of lower concentration. For example, it has been successfully implemented to study patients with acute stroke or brain tumors. Rogers argues that the diffusion of innovations is a general process which is not bound by the type of innovation studied. Diffusion indexes based on dynamic factors have recently been advocated by stock. The salts of sodium resemble potassium in their action on the alimentary tract, but they are much more slowly absorbed, and much less diffusible. How well do diffusion indexes capture business cycles. The good news for book publishers is that i buy nearly all of these books and the others are either legally free, or from the library.
Now in its fifth edition, diffusion of innovations is a classic work on the spread of new ideas. Glossary for oecd composite leading indicators and business. Diffusion indexes a barometer of the economy created date. For example, they may be asked to say whether the order books are higher.
The first step in computing the diffusion indexes is to calculate if a component increased, decreased, or had no change. Diffusion index cfnaidiff from may 1967 to feb 2020 about diffusion, indexes, and usa. The editors of the website will contact all major publishing houses, offering to present any information about recently published books on diffusion aspects. Watson woodrow wilson school, princeton university, princeton, nj 08544, and national bureau of economic research. In other words, it measures how many stocks advanced from the close of the prior session. A diffusion index di provides a summary of answers to multiplechoice. Macroeconomic forecasting using diffusion indexes james h. Empirically, they assemble data on sixtyone democracies between 1990 and 2015 to assess the performance and legitimacy of democracy.
Diffusion indexes and a statistical test for predicting turning points in. An index is a pointer, like the index finger for example. In osmosis though, the movement has to occur across a semipermeable membrane. A diffusion index is a method of summarizing the common tendency of a group of statistical series. In econometrics, a diffusion index also known as a dynamic factor is a series which measures the comovement of many time. How to compute diffusion indexes the conference board.
The term diffusion index can be defined as follows. Solutions to the diffusion equation mit opencourseware. I believe they were all made by pat minczeski on the wall street journal. So the reader can regard the present book as the third volume in a threevolume set on the diffusion of innovations. A diffusion index of monthly employment levels across industries measures the degree to which a growth in employment levels in a population is made up of growth in all industries versus sharp growth in just a few industries. It is also used in economics and statistics to see how. For a diffusion index the percentage of respondents for each category.
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