Sensors costs

With reduced sensor cost the range of appHcations now includes thermal vision (2,3) industrial processing, industrial security, poHce work (3), maritime safety, airline safety and vision enhancement for night driving and flying and weather sateUites. For these appHcations, the thermal sensor typically uses a broad spectral band to achieve highest sensitivity. 

Most UV photodiodes have a sealed metal TO package with an entrance window made of glass or special UV-transmitting glass. A TO housing is extremely reliable but it often counts for a non-negligible part of the sensor costs. Cheaper housings that should be favored for consumer-product applications like in household appliances are hard to find. Full-plastic encapsulation requires a UV-transpar-... 

Sufficiently cheap UV photodiodes are available but they are not visible-blind. Filters have to be used, but they raise the costs. Sufficiently selective photodiodes are also available but they are too expensive, mainly due to their only recently established technology. The sensor costs have been a limiting factor in two application fields of UV sensors, namely water disinfection and combustion monitoring, on the industrial as well as on the household scale. 

In the near future, UV photodiodes made from polycrystalline wide band-gap semiconductors may fill the gap in the market. Although they have a lower sensitivity (photocurrent per area) they promise to have a better merit-rating in terms of photocurrent per sensor costs. The other major drawback of polycrystalline photodiodes, the risetime of micro- to milliseconds, is not relevant for household applications. Fuji Xerox Laboratories in Japan are developing visible-blind UV photodiodes made from polycrystalline GaN [12], while twlux AG in Berlin, Germany is developing visible-blind UV photodiodes made from polycrystalline titanium dioxide [13]. A prototype is shown in Fig. 5.45. 

A3 It is well-known that, if an advanced sensor is available and capable to measure a chemical component within the medium, it is easier to implement the sensor at the output of the process rater than at the input. This fact is justified by several causes such that i) the measuring range of the sensor, the presence of suspended solids and the sensor cost [3]. Then, the total concentration of organic substrate in the influent ST,in is assumed to be unknown, piecewise constant and bounded (i.e., < ST,in < Sipf ). 

The sensors are available as a stand-alone entity for R D and development purposes and can be utilized with any network analyzer operating over the frequency range from 0.5 GHz to 10 GHz. KDC can also provides a cost-effective network analyzer with internal software to calibrate microwave parameters against process parameters. Custom design programs to meet specific applications can also be undertaken. Sensor costs are on the order of 3,000 KDC network analyzers cost approximately 24,000. 

One of the major questions in control system design is the selection of process measurements. An important deficiency of state variable control is that measurements or estimates of all state variables are required. Usually only a few of the states can be monitored instantaneously, because of sensor cost or time delays caused by the need for chemical analysis. Distillation... 

We assume we need accuracy of 3% in stream 1 and 2% in stream 2 allowing only one gross error nf= 1). The sensor precisions, flowrates and sensor costs are given table 1. 

Tablet. Precision, Flowrates, Sensor Cost of Example 1...

Stream Sensor Precision (o-j) Flow Rates (Fj) Sensor Cost... 

Often, most of the functionality of modern automotive sensors is dominated by the sensing elements, which are typically fabricated by one of the above processes. In contrast to their enormous impact on the function of the sensor, the cost added by these sensing elements is normally rather low - approximately 10-25% of the overall sensor cost. Unfortunately, state-of-the-art test methods, which have been developed for testing conventional electronic devices, turn out to be inappropriate or insufficient for testing sensing elements. 

Despite the established sensing approach, in particular for gas phase measurements, extensive studies of optical O2 sensors are still continuing in an effort to enhance sensor performance, reduce sensor cost and size, simplify fabrication, and develop an O2 sensor that is compatible with in vivo biomedical monitoring [56]. Development of field deployable, compact sensors such as those envisioned for the structurally integrated OLED-based platform is therefore expected to be beneficial for the varied needs of gas... 

In attempts to develop field-deployable sensors, efforts focus on, e.g., enhancing sensor performance, reducing sensor cost and size, and simplifying fabrication. We are therefore developing a compact PL-based O2 sensor to evaluate a fully integrated platform, where the PL excitation source is an OLED array and the PD is a p-i-n structure based on thin films of hydrogenated amorphous Si (a-Si H) and related materials, or nanocrystalline Si [18]. 

Failure rate of sensor Failure rate of processor Sensor cost Processor cost... 

In clinical analysis, precision, accuracy, speed, and low cost are important considerations. These goals have sometimes been achieved by unusual devices, e.g., disposable potentiometric cells made by planar multilayer film technology, similar to photographic films. Reduction of sensor costs has been attempted by mass production of sensors using technologies of the semiconductor industry (ISFETs). There still appears to be some instability problems with ISFET devices and they do not appear to be in routine use in the clinical field. 

The objective function is computed by summing up the sensors costs and a sum of the measure (Pj) of the projected standard deviation (O.) of the key performance indicator i resulting from the sensitivity analysis matrix obtained by solving the linearized langrange formulation as defined by Heyen et al. (1996) ... 

Table 3. Summary of the sensor system optimization and sensor costs.

Low sensor cost The sensor is made from a low-cost material, so it is well suited for disposable sensors. 

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