Black box


Identification of the material properties as an estimation of transfer function (TF) for the black box model. In this case the problem of identification is solving according to the results of the input (IN) and output (OUT) actions. There is a transfer of notion of mathematical description of TF on characterization of the material. This logical substitution gives us an opportunity to formalize testing procedure and describe the material as a set of formulae, which can be used for quantitative and qualitative characterization of the materials.  [c.188]

Figure 1. Dynamic model of testing of the material as a black box , where IN - loads and actions OUT - response of the material as measuring characteristics N - noise (combination of uncertain factors) Figure 1. Dynamic model of testing of the material as a black box , where IN - loads and actions OUT - response of the material as measuring characteristics N - noise (combination of uncertain factors)
Increased trust in pattern recognition The active user involvement in the data mining process can lead to a deeper understanding of the data and increases the trust in the resulting patterns. In contrast, "black box" systems often lead to a higher uncertainty, because the user usually does not know, in detail, what happened during the data analysis process. This may lead to a more difficult data interpretation and/or model prediction.  [c.475]

HyperChem should not be viewed as a black box that computes only what its designers thought correct. It has an open architecture that makes it possible to customize it many ways. As far as is possible, the parameters of molecular mechanics and semi-empirical calculations are in the user s hands. As the techniques of software engineering advance and our expertise in building new  [c.157]

Drum and Bulk-Box Filling. 21-56  [c.1909]

Bulk box, 600/600 (test in lb for both pieces), laminated inner lining, approximately 41 X 34 X 36 in (1040 X 865 x 915 mm) includes special wood pallet and 8-mil (0.2-mm) blown low-density PE liner. 35.00 5.00 0.142 "Flat sheeting.  [c.1947]

Drum and Bulk-Box Filling This process consists of three operations setting up, filling and weighing, and closing. Because setting up bulk boxes is cumbersome, a well-methodized workplace, equipped with work aids, is recommended. Weighing and filling can  [c.1964]

Perform black box approximations knowing only the design specification requirements. This results in estimates of semiconductor power losses, peak currents and voltages. It may also indicate to the designer that the chosen topology is inappropriate and a different choice is necessary. It also allows the designer to order any semiconductor samples that may be required during the breadboarding phase of the program.  [c.8]

The "Black Box" Considerations for Switching Power Supplies  [c.34]

Table 3-3 The "Black Box" Estimates for Losses within the Various Topologies Table 3-3 The "Black Box" Estimates for Losses within the Various Topologies
This completes the black box estimates portion of the design program. As one can see, some very useful information can be determined by performing these estimates.  [c.37]

To start the design, the peak eurrent should have been estimated during the proeeeding blaek box estimation phase. The eore style and material should have also been seleeted (refer to Appendix D). This time an air gap is neeessary for reliable operation.  [c.42]

Black box predesign estimates  [c.101]

Black box pre-design considerations (refer to Section 3.4)  [c.105]

Black box predesign considerations  [c.123]

Black box predesign estimates  [c.163]

Predesign blaek box eonsiderations  [c.171]

The Black Box Considerations for Switching Power Supplies 34  [c.271]

When dynamic simulation is used for process equipment and process safety design, it is necessary to ensure the model s assumptions are conservative. For example, if dynamic simulation is used to calculate the pressure rise in a heat exchanger after a tube rupture, the highest calculated pressure may be used as the design pressure. If all the assumptions are conservative, the actual heat exchanger pressure will not exceed the design pressure during a tube rupture. Despite this conservative approach, equipment design conditions calculated by dynamic simulation are often much less severe than the conditions determined by conventional calculation methods. This often leads to considerable cost savings. Dynamic simulation software should support the addition of user-written code for specialized equipment and control system models. For example, an unusual fractionator tray design or a correlation for an off-design heat transfer coefficient may have to be programmed into a user-written model. Dynamic simulation of "first-of-a-kind" plants often requires developing a dynamic model for a new equipment item. A control system vendor s DCS algorithm may also need to be programmed into a custom PID controller model. Users may need to add their own fluid property systems to increase computational efficiency and handle unusual systems. "Black box" models are too restrictive to provide realistic models for most dynamic simulation problems.  [c.46]

Catalytic crackings operations have been simulated by mathematical models, with the aid of computers. The computer programs are the end result of a very extensive research effort in pilot and bench scale units. Many sets of calculations are carried out to optimize design of new units, operation of existing plants, choice of feedstocks, and other variables subject to control. A background knowledge of the correlations used in the "black box" helps to make such studies more effective.  [c.17]

Black box modelling for dynamics  [c.293]

TREATING THE COMPUTER AS A BLACK BOX  [c.354]

The most common types of errors are probably those that occur because operators treat the computer as a black box, that is, something that will do what we want it to do without the need to understand what goes on inside it. There is no fault in the hardware or software, but nevertheless the system does not perform in the way that the designer or oper-  [c.354]

The classical human factors engineering/ergonomics approach to human error was essentially based on a "black box" model of human behavior that focused primarily on information inputs and control action outputs. In this section a more modem perspective, based on approaches from cognitive psychology, is introduced. At one level, the cognitive perspective is still concerned with information processing, in that it addresses how people acquire information, represent it internally and use it to guide their behavior. The key difference from the HF/E approach is that the cognitive approach emphasizes the role of intentions, goals, and meaning as a central aspect of  [c.66]

Although chemical data analysis has become highly automated through the development of computer-aided methods and applications, an effective extraction of new knowledge and information still requires intervention and interaction through the scientist. Especially in the case of complex problems, a successfiil solution is only warranted if human intuition, flexibility, creativity, and expert knowledge are included in the decision process. However, classical, computer-aided data mining methods are usually so-called "black box systems that only allow a very limited or no interposition through the scientist. Furthermore, these approaches often require expert knowledge.  [c.475]

HyperChem should not he viewed as a black box that computes on ly wb at its design ers th ougb L correct, tthasan open architecture that makes it possible to customize it many ways. As far as is possible, the parameters of molecular mechanics and semi-empir-ieal calculations are in the user s baruis. As the tech n ic ues of software engineering advance and onr expertise in building new  [c.157]

Platform scale, autofill cutoff, SFW 1 Bulk box, 3-mil PE hner 15 X 15 X 24. 380 X 380 X 610 Outer 275-lh test DWf liner 600-lb test, DW Staples Insecticide, tech nical grade 40 640 —200 mesh  [c.1960]

Platform scale, autofill cutoff, SFW, automatic staple closer 1 Bulk box 41 X 34 X 36 1040 X 860 x915 Inner, outer boxes 600-lh test, DW kraft hoard Staples PE 30 481 V -in pellets  [c.1960]

Today s eddy eurrent brake system is far superior to the meehanieal switeh-operated units of the past. Modern eontrols take advantage of all of the sophistieated logie found in mieroproeessor teehnology. This eontrol system is funetionally deseribed in Figure 4-147. Eaeh blaek box represents a separate eontrol funetion with a master eontrol ealled the eddy eurrent brake eontroller.  [c.267]

This preliminaty step in the design phase, predetermines some of the major parameters the switehing power supply will exliibit. This allows the designer to determine whether his or her ehoiee of topology is eorreet and also allows the designer to order eomponents for the breadboard, long before they are required. It also results in knowing some of the partieularly important parameters needed later during the design. For determining the blaek box estimates, the designer need only know the environmental parameters from the design speeifieation and then treat the future power supply as a blaek box that is, a box with only input and output lines emerging from it (refer to Figure 3-17).  [c.34]

The standard recovery rectifiers used in the rectifier bridge must accommodate the highest average current expected which occurs at the ac low-line voltage. This has been calculated during the predesign estimates (black box considerations). The rated forward current should be more than 2 A and minimum blocking voltage should be twice the maximum high ac line crest voltage. This is more than 764 V. A 1N5406 would be a good choice.  [c.132]

Controlling high frequency noise generation and radiation is the blackest of the black box art in switching power supply and product-system design. It is a subject that warrants a book all to itself and it is the final area that will interfere with the release of your product into the market. This appendix cannot adequately cover the subject, but will overview the major considerations involved with product design.  [c.241]

An interesting and important feature of a neural network trained using baek-propa-gation is that no knowledge of the proeess it is being trained to emulate is required. Also, sinee they learn from experienee rather than programming, their use may be eonsidered to be a blaek box approaeh.  [c.358]

Stirred tanks are the most eommon form of erystallizers. Nevertheless, due to high loeal gradients of the energy dissipation, the fluid dynamies are not well understood and depend to a large extent on the geometry of the vessel. Different forms of impellers, baffles and draft tubes ean produee very different flow fields. As a stirred tank eontains a moving impeller, the fluid eells surrounding the impeller are modelled as rotating bloeks in CFD (Bakker etai, 1997). A sliding mesh teehnique has been developed to aeeount for the movement of the rotating impeller grid relative to the surrounding motionless tank eells. Xu and MeGrath (1996) eompared the sliding mesh simulation results for a stirred tank with experimental laser doppler anemometry (LDA) data and found that the data eorresponded very well. An alternative to the sliding mesh teehnique is the momentum souree model, where the impeller region is modelled as a blaek-box souree of momentum. In this ease, however, experimental data eoneerning the forees aeting on the impeller are neeessary. Furthermore, no loeal data in the impeller region ean be obtained (blaek box) when using the momentum souree model. For a sliding mesh simulation, on the other hand, no experimental data are neeessary and the flow field in the vieinity of the impeller is readily obtained.  [c.48]

Most of the literature in eontrol of eontinuous erystallizers is based on a singleinput single output (SISO) eontrol strueture. Different eontrolled variables and manipulations have been suggested based on the relative ease and aeeuraey of on-line measurements and their effieieney in effeetively addressing set-point traeking and disturbanee rejeetions. Both linearized physieal models and blaek-box models have been suggested for the eontroller design, as reviewed by Sheikh (1997) as follows.  [c.291]

Jager etal. (1992) developed a black-box model based controller for a 970-litre crystallizer again using a dilution unit and on-line measurement with light scattering devices together with mass flow meters. System identification techniques were used these offer a lower order state space model for multi-variate analysis. A three-step identification procedure was employed to obtain the model. In the first step, the ARX model (Ljung, 1987) was used. The second step involved transformation of the ARX model into a state-space representation through approximate realization (Damen and Hajdasinski, 1982). Finally, the model was used as an initial parameter combinatory for fitting the actual data. Uncorrelated white noise signals were added to the data used, because they could be added to process inputs simultaneously without affecting the ability of the identification algorithm to distinguish the contribution of each individual input to the output signal, thus allowing effective use of data. A model derived through these steps was used to establish relationships between inputs including heat input, product flowrate and rate of fines dissolution, and the output measures, which were third moment and mass based average size.  [c.294]

The approach developed from a general change in emphasis in applied psychology during the 1970s and 1980s, from viewing the human as a passive black box, analogous to an engineering component, to the view that individuals were purposeful in that their actions were influenced by future goals and objectives. The cognitive systems engineering approach is particularly applicable to activities such as planning and handling abnormal situations. Its methods include cognitive task analysis, which focuses on information processing failures, and the use of decision support systems of varying levels of sophistication to assist in the handling of abnormal situations. To date, the application of the approach has been limited in process plants, although the development of interest in the area by human factors specialists has stimulated research into the nature of the skills possessed by process workers. Nevertheless, this approach is the most comprehensive in terms of evaluating the underlying causes of errors. This means that it has particular relevance to analyzing the causes of recurrent errors and for predicting specific errors that may have serious consequences as part of safety analyses.  [c.45]


See pages that mention the term Black box : [c.199]    [c.1958]    [c.35]    [c.35]    [c.114]    [c.460]   
Power supply cookbook (2001) -- [ c.0 ]