#### **2. Materials and Methods**

#### *2.1. Study Area*

Genoa is a port city of the Mediterranean and capital of Liguria (north-western Italy). The municipality, whose current size dates back to the 1926 "Grande Genova" project, is 240.29 km2 wide and the coastline 35 km long. The most ancient core of the city, the yellow area in Figure 1, was smaller (c. 11.45 km2 ) and was roughly located between the city's two main streams: the Bisagno in the eastern part, and the Polcevera in the West. From a geological point of view, the study area is largely constituted by marly limestones, marls, and clays in Flysch sequences of Upper Cretaceous, while the western part, in the Polcevera Valley, is dominated by shales of Lower Cretaceous [36–38]. The two formations are found both as outcrops and bedrock. Another important lithotype, today largely hidden by the urban structure, is constituted by stiff fissured Pliocene clays, exclusively found in the historical center [37–42]. Morphology is characterized by many small and steep catchments, mostly oriented orthogonally to the coastline, originating from the neotectonic activity [42].

**Figure 1.** (**A**) Study area and areas of interest. (**B**) The *geological sketch map* box: (1) waterfront embankments; (2) alluvial deposits; (3) slope deposits; (4) stiff fissured clays; (5) shales; (6) marly limestone with clayey shales interlayers.

The first permanent settlement dates back to the pre-Roman period. In the Middle Ages, Genoa developed around the old city core with an East–West direction along the coastline [43]. Urban sprawl over the hills, with a South–North direction, and along the coast developed in more recent times [44] (Figure 2). In the early 19th century, the two main valleys, the Polcevera to the West and the Bisagno to the East, were characterized by an agricultural landscape with a dense pattern of small fields across the floodplain and terraces over the slopes with a prevalence of vineyards and olive orchards [45,46]. Terraces are only partly visible in the current landscape and have been largely obliterated by more recent urban structures, decametric retaining walls, and high blocks of flats of the second half of the 20th century [47]. Urban expansion brought hydraulic works in the two valleys, with progressive narrowing of the riverbeds and the establishment of new

urban areas in the floodplains in the early 20th century up to the 1930s [12]. It is estimated that loss of agricultural surfaces between 1820 and 2014 in the Bisagno Valley was 57%, while woodland and new urban areas increased respectively by 248% and 750% [45]. In the second post-war period, the Promontory of San Benigno, exploited for the extraction of marly limestone as building material from the Middle Ages, was completely excavated. The complete removal of San Benigno Promontory allowed territorial continuity between Genoa center and its western suburbs, with intense urban saturation of many areas, including the former rock quarry [34].

**Figure 2.** Urban sprawl in western Genoa (**a**) Vinzoni (1773) "Il dominio della Serenissima Repubblica di Genova in terraferma (Riviera di Ponente)"; (**b**) Carta degli Stati Sardi in Terraferma di S. M. il Re di Sardegna "Minute di campagna scale", scale 1:9,450 period 1815–1823; 1:25,000 scale topographic map of the Italian Military Geographic Institute of 1878 (**c**) and 1934 (**d**).

#### *2.2. Materials*

Analyzed material can be divided into two subgroups: historical cartography and current cartography.

The most important document is the "*Carta Generale di Difesa di Genova*" by engineer Ignazio Porro (1848). For the purpose of this research, we analyzed the digitalized version of black and white photographs of the 74 original plates (scale 1:2'000) of the "*Carta Generale di Difesa di Genova*" depicting a large part of the current urban area. Porro, who was engaged by the Kingdom of Sardinia for the production of the map, can be considered as a pioneer of topographical surveying and is the inventor of the Porro prism for binoculars.

The map represented with high detail the system of military fortifications and the morphology of the Genoa area, providing topographical information for urban planning aimed at improving the military defenses of the city. Starting from data acquired by Napoleonic topographers and unpublished documents by astronomer Baron De Zach (1816–1817) and with the help of engineer Giulio D'Andreis, Ignazio Porro carried out a new triangulation using mountains around Genoa as reference points and applying for the first time in Italy the tacheometry technique, which he appositely improved for the purpose of this project [48].

The final work consists of 74 plates on a scale of 1:2'000 with a reference system related to the Lanterna (Lighthouse of Genoa Harbour), with 10-m-interval contour lines.

This cartographical product is one of the first Italian examples of topographical representation with contour lines. Overall, it is a metric planimetry based on relative coordinates and with the North direction coaxial to the plates' vertical squares

The area analyzed in this research is in the central part of the city and the coast nearby and is covered by 7 of the 74 plates produced by Porro. These are plates n◦ 42, 52, 53, 62, 63, 72, and 73, according to Porro's numbering system.

Notably, the analysis focuses on particularly interesting sections from a historical and urban geomorphological point of view (see Figure 1): (I) Sant'Agata Old Bridge (included within sheets n◦42 and 52); (II) Circonvallazione a Monte (included within sheets n◦52, 53, 63); (III) San Benigno Promontory and via Digione area (both included within sheets n ◦ 62 and 72; and (IV) Polcevera Viaduct area (i.e., Morandi Bridge area), entirely included within sheet n◦ 73.

Cases I (Sant'Agata Old Bridge) and IV (Polcevera Viaduct) are located in alluvial plains respectively of the Bisagno and Polcevera Streams, while II (Circonvallazione a Monte) and III (San Benigno Promontory and via Digione area) are hillside case studies, very significant for the substantial urban and morphological modifications they went through during the years, particularly due to rock excavation.

Modern cartography consists of sheets of the Regional Technical Map of Liguria on a scale of 1:5'000 ("*Carta Tecnica Regionale"* ed. 2007), digital terrain models (DTMs) with a 1-m resolution and equivalent scale of 1:1'000, and orthophotos with a 10-cm resolution. The last two constitute the LiDAR aerial survey that Genoa Municipality commissioned in September/October 2018 across the municipal area (Figure 3).

**Figure 3.** (**a**) Porro Plate n◦52. (**b**) The same area today, overlay of Regional Technical Map and DTM LiDAR.

In addition, stratigraphic information from the database of Regione Liguria [49] and boreholes promoted by the *Special Commissioner for the reconstruction of Polcevera viaduct*, after the Morandi Bridge disaster [50], were used. These are fundamental data sources in order to reconstruct the deepness of the contact interface between landfill material and natural rock/sediment. These point data were integrated with the digitalized contour lines and are the input for interpolation calculation.

#### *2.3. Methods*

The methodology is summarized in Figure 4. Two different GIS software were used, QGIS and GRASS, while the accuracy of the old cartography was defined with MapAnalyst.

QGIS was used for the georeferencing and digitalization of contour lines, while GRASS was used to generate the digital elevation model (DEM) and for statistical and algebraic analysis of the difference of DEMs (DoDs) system [51–54].

The analysis initially seeks to define the intrinsic quality of maps, considering that the accuracy error of old maps on the x-y plane (*RMSEH*) is given by the sum of various factors summarized in the following relation (1):

$$RMSE\_H = \left( RMSE\_s^2 + M \cdot RMSE\_m^2 + M \cdot RMSE\_d^2 \right)^{0.5} \tag{1}$$

where *RMSES* is the error introduced by the ground survey, *RMSEm* is the map error, *RMSEd* is the digitization error, and *M* is the map scale factor [55,56].

As Porro himself described in his relation [57], topographical surveying was affected by an azimuthal instrumental error (RMSE) of 0◦ 0' 70'', which meant a real deviation of 0.33 m on the x-y plane at a distance of 1 km.

Moreover, digital images are the product of a process of paper maps photography that has very likely produced perspective distortions (*RMSEd* ). In addition, it has been observed that original images show deformations also due to paper deterioration processes (*RMSEm*).

#### - Accuracy analysis with MapAnalyst

The first passage entailed a monitor comparison between the old map and the current orthophoto/topographical map aimed at identifying the perimeters of medieval, Renais-

sance, and 18th/19th-century palaces still found in Genoa's urban fabric. Once reference points of both maps were found, ground point control (GCP) positioning was carried out. These are common points between plates of the Porro Map and the current cartography, using firstly orthophotos and secondly OpenStreetMap only as auxiliary images for references of place names.

MapAnalysts simulates a georeferencing process, which consists in imposing a geographical reference system known to the target image. This dislocation causes variable image distortions depending on the desired reference system. However, the output provided by MapAnalyst is not a ground control point (GCP) but a statistical basis on the old map accuracy compared to the modern one.

For this analysis, three geo-referencing algorithms, available in MapAnalyst, were applied: *Linearised Helmert*, the *Affine transformation with 5 parameters*, and the *Affine transformation with 6 parameters*.

Once the statistical basis was obtained, the same procedure was applied using QGIS, identifying for each image the same configuration and the same number of GCPs allocated in MapAnalyst.

Images in QGIS were georeferenced with the linearized Helmert algorithm. This algorithm does not distort an old image; rather, it roto/translates it, minimizing the deviation between the old image and the geo-referenced one. The adopted reference system is Gauss-Boaga Roma 40 (EPSG 3003).

In general, it is possible that some points might be higher than RMSE. In this case, a threshold value was arbitrarily decided, slightly higher than the error estimate under which the variance between Porro and modern topography can be considered acceptable.

In cases where the distortion was higher than the threshold, additional GCP were assigned by iteration until the desired effect was reached.

This was done for each single map section, which falls within a single or two or more plates. The process allowed us to minimize the distortion error as each plate is separate and can be geo-referenced singularly.

Subsequently, contour lines were digitalized through a linear geo-vector by assigning the relevant elevation above sea level. Once this operation was completed, the vertexes of these isolines were extracted.

In the hillside area (Circonvallazione a Monte, San Benigno Promontory, and Via Digione), this operation was sufficient and complete.

In floodplain areas (Sant'Agata Old Bridge and Polcevera Viaduct) where contour lines are not frequent or not visible due to the presence of buildings, another data source was represented by borehole stratigraphy (Figure 5) [49,50].

In particular, the ancient interface surface between landfill material and natural rock/sediment was considered, but only in cases where the borehole stratigraphy indicated post-industrial landfills that included traces of cement, industrial bricks, etc.

Moreover, since riverbed areas in the Porro Map lack spot elevations, it was decided to conceptually match the old topographical surface with the current situation. This allowed us to bind the interpolation to the thalweg in order to maintain the morphology of typical cross-sections of Ligurian riverbeds.

Elevations of the current riverbed were extracted from LiDAR and assigned to the old riverbed as spot elevations. In this way, the same vector file gathered elevations extracted from contour lines: at the interface between landfill material and natural sediment/rock substrate and in the two riverbeds, bearing in mind that no significant natural process occurred, such as severe erosion or intense sediment accumulation due to flooding, that changed the floodplain terrace elevations between Porro's survey epoch and the late 1800s, when intense urban sprawls began, unlike the phenomena described in [58–60].

**Figure 5.** An example of a borehole with translated stratigraphy used for this research.

#### - Interpolation and DoDs with GRASS GIS

Since hand-drawn graphical elements of the Porro map have an equivalent resolution of 2 m (1 mm to the naked eye on a scale of 1:2'000), previously obtained elevation data were interpolated on a raster map with a 1-m resolution, also to reduce potential vertical errors due to horizontal offset between the old and current map, according to a methodology explained by Stoker et al. [61].

This was carried out in GRASS GIS through three different steps: (1) the *v.surf.rst* command [62], an algorithm based on spline with smooth and tension, used for preliminary interpolation that allowed us to convert elevations into a first raster dummy surface; (2) from this surface, a vector points cloud with casual location was extracted with the *r.random* command; (3) these points were interpolated a second time with the *v.surf.rst* command, obtaining a smooth surface, not affected by classic interpolation errors, such as quad-three, gradient gaps, etc. [63].

Moreover, once output raster maps of the five case studies were obtained, an assessment on vertical unreliability was carried out according to the following relation [54]:

$$
\varepsilon\_{\mathbb{Z}} = \varepsilon\_H \cdot \tan \llcorner \tag{2}
$$

where *εZ* is the elevation error caused by horizontal offsets on a sloping surface, *εH* is the horizontal error, and α is the local slope.

In slopes characterized by α < 45◦ gradient, potential vertical offsets between the old and current cartography are less than the horizontal one. In contrast, if angle α > 45◦ , the quantification of the vertical offset is crucial as this is higher than the horizontal one.

The maximum vertical offset RMSEZij MAX [64] was calculated, corresponding to the cell with the highest slope degree, according to relation (3), in order to have full knowledge of the limits of the extracted output:

$$\text{RMSE}\_{\text{Zij}\,\text{MAX}} = \text{RMSE}\_{H} \tan \text{ S}\_{\text{ij}\,\text{MAX}} \tag{3}$$

where *RMSEH* is the horizontal error for the map, and Sij MAX is the maximum slope in a i-row and j-column grid cell of the output raster map.

Furthermore, sea level rise in the period 1884–2009 [65] was considered in order to quantify the heights' vertical offset between modern and 1830s sea level measurements.

The resulting old DEMs were subtracted from the 1-m-resolution 2018 LiDAR of Genoa Municipality, obtaining the various DoDs, where positive areas correspond to fillings and negative ones to excavations [15].

#### **3. Results**

The methodology adopted produced the following results:

From a first modelling process through *MapAnalyst*, it was possible to quantify potential errors by applying the linearized Helmert transformation, the affine transformation with five parameters, and the affine transformation with six parameters.

It was observed that the accuracy in old cartography increases in consolidated urban areas; this is due to the higher number of reference points that Porro and his team could use, compared to hilly areas. This also explains why the number of GCP couples is higher in plates of urban areas. This makes them more reliable than plates of rural areas characterized by less GCP couples. The GCP minimum number for each couple of images is 16 as shown in Table 1, alongside the error estimations for each plate.

**Table 1.** Georeferenced plate numbers with standard deviation, RMSE computed with various algorithms, and the number of used GCP.

An acceptable deviation threshold of 10 m on a x-y plane between old and current cartography was arbitrarily established, a slightly higher value than the RMSE (Affine 5) of sheet n◦73 (the least accurate and located in areas with no urban settlements at the time of Porro).

Interpolation obtained through *spline with smoothing and tension* at a 1-m resolution increases the smoothness of old topographical surfaces, generally characterized by a lower gradient than current ones. In addition, by interpolating contour lines it was possible to follow riverbeds and/or erosion landforms of ancient, often ephemeral, streams, now completely obliterated by anthropic landforms.

The total surface of the calculated raster maps is 1.79 km2 , of which only 0.2% have a gradient > 45◦ , and the cell with the highest gradient has a value of α = 84◦ so that RMSEZijMAX = 28.02 m, obtained through relation (3) with RMSEH = 4.09 (Sheet 72, Helmert in Table 1).

In the remaining part (99.8%), the vertical offset value is less than the horizontal one.

The case studies, all less than 2.5 km from the coastline, lie within 150 m asl. In particular, the Sant'Agata Old Bridge and Polcevera viaduct areas are respectively included between 5.2–60.3 m asl and 4.92–82.89 m asl, while via Digione and San Benigno Promontory are located respectively between 18.02–111.69 m asl and 10.02–92.41 m asl. Circonvallazione a Monte lies between 57.47 and 130.74 m asl.

The heights' vertical offset between modern and 1830s sea level measurements is about 25 mm with an average rate of 1.1 mm/year. Considering an average slope of 16.94◦ for the old DEM hilly areas, as obtained only by the Porro's isolines interpolation, an offset

of 0.25 m leads to an average x-y shifting of 0.9 m, which may be considered as a negligible value.

For what concerns the DoDs, outputs can be divided into three different macro-groups. The first group is characterized by a high frequency of positive differences. This is the case of floodplain areas, including Sant'Agata Old Bridge (Figure 6) and Polcevera Viaduct (Figure 7). As already discussed, the preliminary assumption that old and current surfaces of Bisagno and Polcevera riverbeds precisely overlap means that the elevation difference in the DoDs equals to zero. Instead, there is a significant difference for what concerns current artificial embankments, which is maximum in their immediate proximity and tends to decrease with distance, reaching almost zero values near the foothill. The average thickness of the alluvial plain is around 2.45 m.

**Figure 6.** Sant'Agata Old Bridge: (**a**) Old surface; (**b**) DoD with the medieval and modern trace.

**Figure 7.** Polcevera Viaduct: (**a**) Old surface; (**b**) DoD.

The case of Polcevera Viaduct is even more complex due to the numerous anthropic landforms (*sensu* Rosenbaum) (i.e., railway, industrial sites, etc.).

Along the slopes, local fillings with differences between 10–15 m are found.

The second group is characterized by a greater occurrence of negative differences. This is the case of via Digione and San Benigno Promontory (Figure 8). Except for slight positive differences of c. 2–3 m in the slope's upper side, significant negative differences, around 60–75 m, are noticed.

**Figure 8.** San Benigno Promontory and Via Digione: (**a**) Old surface; (**b**) DoD; (**c**) Via Digione cross-section; (**d**) San Benigno Promontory cross-section.

The third group is represented by Circonvallazione a Monte (Figure 9). In this case, it was not possible to identify areas characterized by a high frequency of positive and negative values. Amongst the negative differences there are values below 20 m, while the positive ones can reach 12–15 m. Compared to previous cases, areas with values around zero in Circonvallazione are rare.

**Figure 9.** Circonvallazione a Monte: (**a**) Old surface; (**b**) DoD.

#### **4. Discussion**

The analysis shows how an average offset < 10 m between the current cartography and the "*Carta Generale di Difesa di Genova*" can be reached by repeating the geo-referencing process. This value can be considered acceptable to distinguish between natural and anthropic landforms at large-scale maps (1.10'000–1.5'000).

The difference between anthropic and natural landforms, however, is only visible for the period between present day and the second half of the 19th century. Anthropic landforms before this period can be easily confused with natural morphologies. For this reason, the Porro cartography and derived products can be integrated by using older cartographies, although these can lack geometrical accuracy. In addition, paintings, topographical views, and historical photographs can offer insights into past landscapes [66].

For instance, the raster of Figure 10a shows a gently sloping area along the left side of the stream with a regular pattern and constant NE-SW direction. From the analysis of the Porro cartography, it is not possible to establish whether this is a natural morphology or a filling landform of the period before 1848 [15].

However, the painting of Figure 10b, made in 1853 from previous *en plein air* sketches, shows that this can be a filling of the floodplain area of the Polcevera Stream confined by a consistent stone retaining wall. Here, starting from 1850, various railways lines connecting Genoa to northern Italy were established. The section of Figure 7b, near the viaduct, shows that the thickness of the two railway embankments is around 5 m.

The area of Sant'Agata Old Bridge is also characterized by dense urbanization, although the evolution of anthropic and natural landforms is less complex. Here, a consistent filling dating back to the period between late 19th and early 20th century is found, related to the Bisagno Torrent narrowing. The bridge of Sant'Agata (Figures 6b and 11a) was made in the medieval period along the track of the old Aurelia road and consisted of 28 arcades for a total length of 360 m. Currently, the new bridges are only 50 m long, providing evidence of the significant narrowing of the Bisagno Stream riverbed [12]. Alongside Polcevera Stream, the Bisagno is currently one of the mostly exposed to geo-hydrological risk Italian rivers. Their narrowing is one of the reasons of the frequent flood events of the two streams. In the 1950–2015 period, 5 floods with discharge between 700 and 1000 m3/s occurred [12,45,67].

**Figure 10.** (**a**) The output of Polcevera viaduct, in purple dotted line the Campasso area; (**b**) Left bank, elevated area with embankment sustaining wall in the Campasso area (view by Carlo Bossoli, 1853).

**Figure 11.** (**a**) Sant'Agata Bridge in the background (painting of Giuseppe Bisi, c. 1825); (**b**) Ancient Genoa: outside the city walls, over the hills, the site where Circonvallazione a Monte currently lies was characterized by a rural landscape (painting, unknown author, c. XV-XVII century); (**c**) San Benigno Promontory not yet excavated and the Lighthouse (*La Lanterna*) in the background; (**d**) Via Digione landslide (1968).

During intense rainfall events (>50 mm/h, [44,45]), minor sink-holes due to collapses of culvert-arches of underground streams took place [42], something that is also very likely to occur in the Circonvallazione a Monte area.

Circonvallazione a Monte crosses an area characterized by 11 minor catchments less than 3 km2 in size [42]. As shown by Figure 9, filling and excavation anthropic landforms analyzed with DoD are quantitatively commensurate to current topography, constituted by excavations and significant decametric retaining walls (Figure 11b). These walls, built on limestone bedrock, are not monitored nor is their deterioration state known. Local building collapse episodes due to the subsidence of significant landfill materials thickness is indicated in small valleys that have been filled since the second half of the 19th century [42].

However, the most significant excavation case is San Benigno Promontory, where an entire slope was removed. Only considering the southernmost part of the slope, from the excavation face edge, more than 10.79·106 m3 of rock were removed between the late 19th century and 1960 (Figure 11c). This value was obtained by DoD in Figure 8, excluding the area of via Digione [68]. Here, another limestone quarry, completely excavated and characterized by the establishment of new buildings in the post-war period, was affected by a landslide in 1968, with 19 fatalities (Figure 11d).

Such a product, in addition to having multidisciplinary scientific interest, is also a useful tool for stratigraphy analysis of the buildings' foundation levels and for the production of civil protection maps [69] or multimedia products aimed at raising public awareness on geo-hydrological risk in urban contexts [70–72].

#### **5. Conclusions**

Digital image acquisition of analogic photographs of the "*Carta Generale di Difesa di Genova*" map; its error analysis, georeferencing, digitalization, and contour lines interpolation; and DEMs difference between the derived product and the current DTM (2018) allowed us to develop a specific methodology useful for the study of urban geomorphology. The analysis demonstrated that this specific old cartography can be compared with modern large-scale topographical maps. It provides evidence of the potential use of such historical material to identify and quantify anthropic landforms in urban geomorphology survey and mapping. In particular, it is worth mentioning cadastral maps with no elevations or contour lines and old views depicting past landscapes.

This analysis involved five sample areas that were compared with the topography of Ignazio Porro. The result can be divided into three different categories:

Potential further research can involve broader geographical areas and time frames; from a size point of view, the whole area of Genoa can be covered using the 77 plates made of the Porro map. Assessments of the city's morphometric changes can be carried out by analyzing more recent maps, for instance, geo-referencing and interpolating the IGM (Istituto Geografico Militare) 1:25'000 scale maps [14,71] produced between the late 19th and early 20th century in order to gain a precise city evolution with a 30-year interval.

This approach can be used for other cities that, like Genoa, are characterized by urban and architectural stratification worthy of being discovered and studied. This process would necessarily entail the use of a sufficiently old map or set of maps, which would depict with accuracy the landscape before urbanization took place.

**Author Contributions:** Conceptualization, Francesco Faccini and Martino Terrone; methodology, Martino Terrone and Guido Paliaga; software, Martino Terrone and Guido Paliaga; validation, Pietro Piana, Francesco Faccini and Marco D'Orazi; formal analysis, Martino Terrone; investigation, Martino Terrone and Francesco Faccini; resources, Martino Terrone and Francesco Faccini; data curation, Pietro Piana, writing—original draft preparation, Martino Terrone and Pietro Piana; writing—review and editing, Pietro Piana and Guido Paliaga; visualization, Marco D'Orazi; supervision, Francesco Faccini; project administration, Martino Terrone and Marco D'Orazi; funding acquisition, Martino Terrone and Francesco Faccini All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was financed by Programma Operativo Regione Liguria 2014-2020 - Fondo Sociale Europeo–Asse 3 "Istruzione e Formazione". RLOF18ASSRIC/60/1 "Tecnologie per il monitoraggio integrato e la mitigazione del rischio geomorfologico da frana nella gestione delle reti di sottoservizi" (Scientific coordinator: Francesco Faccini).

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

#### **References**

MDPI St. Alban-Anlage 66 4052 Basel Switzerland Tel. +41 61 683 77 34 Fax +41 61 302 89 18 www.mdpi.com

*ISPRS International Journal of Geo-Information* Editorial Office E-mail<EMAIL_ADDRESS>www.mdpi.com/journal/ijgi

MDPI St. Alban-Anlage 66 4052 Basel Switzerland

Tel: +41 61 683 77 34 Fax: +41 61 302 89 18

www.mdpi.com ISBN 978-3-0365-4123-5


1. Introduction

As a comprehensive technology, industrial automation is a general term for information processing and process control of measurement, manipulation, etc., without direct manual intervention, according to expected aim in machine equipment or production process. Through the application of computer, electronic equipment, control theory, and related process technologies, industrial automation produces the management functions of optimization, detection, control, and regulation of the whole industrial production process to realize the established objectives, achieving industrial production increase, energy saving, consumption reduction, and safe production.

The foundation of intelligent manufacturing is digitalization, networking, and integration. Correspondingly, industrial automation in the era of intelligence will transform centralized control into decentralized enhanced control under the original automation technology and architecture, so that the communication between sensors and the Internet can be seamlessly docked, establishing a highly flexible, personalized, and digital production mode that integrates products and services. In this mode, production automation technology can make equipment more intelligent through self-diagnosis, self-correction, and various functional software to better assist workers to complete production. Therefore, the communication and integration capabilities of automation equipment are required to be stronger, while the automation software needs to have a stronger ability of analysis and processing and data sharing with other software systems of enterprises.

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and eproduction in any medium, provided the original work is properly cited. © 2019 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


**3.4 Interaction**

Interaction being a critical component of both sociocultural theory and sociolinguistics for individuals to mediate human experience of the world requires providing opportunities where students can become active participants of science discourse. Since, explanations are one genre (text) commonly used in scientific communities, providing students opportunities to construct science explanations about science phenomena affords them ways to begin learning to use language in similar ways to scientific communities. The construction of science explanations in the example above is a prime example of how science texts, as in the use of the CER explanation framework, require a carefully constructed text that is coherently and cohesively organized to communicate meaning. This is symbolic of the textual metafunction of SFL. Equally important though is the interpersonal metafunction of SFL for using language as a social semiotic tool for sense-making. Science learners, as text composers, must consider who their intended audience is and what the subject matter is to

#### *Using Language as a Social Semiotic Tool in Virtual Science Instruction DOI: http://dx.doi.org/10.5772/intechopen.101814*

communicate meaning via science explanations. Under these circumstances, students communicate with other students and with the teacher about science-specific concepts and phenomena. Thus, teachers are encouraged to be very intentional in their planning of interaction opportunities to promote student-student interaction in addition to student-teacher interaction. It is important that the interaction opportunities be aligned to both the content and language objectives of the lesson. Interaction opportunities were one of the most experienced pedagogical challenges when the sudden movement to remote instruction was made. Platforms like Zoom permitted the use of breakout rooms, as one way to promote student-student interaction. However, it became quite difficult for the teacher to go from one breakout room to another, and while students were in breakout rooms, teachers were not able to view what interaction might have been occurring in other breakout rooms where the teacher was not present. Because of this, this author proposes the integration of technology platforms and applications that permit the technology resources to promote student-student, student-teacher, and teacher-student interaction in more concurrently visible ways. Some applications that capture the live interaction in whole virtual group (versus small break out groups) are described next.

Padlet is an interactive platform that gives the teacher access to all student communications. The comment posting feature captures language outcomes in written form. In doing so, students are able to post their science explanations. The platform permits the use of videos and links to online simulations for students to interact with content. Padlet also allows the ability to post voice memos. When working with students of CLD backgrounds, such as second language learners (SLL), posting comments onto a Padlet gives SLLs opportunities to develop their writing skills, whereas voice memos, affords them oral language opportunities and practice with listening comprehension. Further, this application provides students with opportunities to mediate science learning using language as a social semiotic tool to make sense of their learning experienced. Other applications such as nearpod have similar features, while online simulations offered by PhET offer great virtual hands-on experience for students to interact with the content via online simulations.

#### **3.5 Scaffolding**

Returning to the content and language objectives component for planning a virtual hands-on lesson, one must also consider the exploration phase of the 5E lesson cycle to intentionally decide what experiences to provide students with to scaffold their learning at the actual development level and assist them to advance to the next potential development level. This must happen at both the conceptual and linguistic levels. Recalling that the use of physical tools provides external mediation opportunities for students, language (specifically the language function of explaining) is one that can be internalized in some form of actual development for SLLs but should always be scaffolding the language tasks at potential developmental levels for second language learning. This approach promotes both content and language development through intentional planning.

In the use of sequential and causal explanations aforementioned, it is important that conceptually, students understand a process first before expected to understand causal conditions of manipulating a process for a specific outcome (effect) to occur. This level of scaffolded instruction targets both conceptual understanding and linguistic communication to experience science and communicate about science

phenomena experienced. Further, for CLD students who are learners of a second language, linguistic scaffolding also develops their language competence and proficiency over time, hence why language practice through interaction opportunities are so critical for this student.

## **4. Discussion**

The integrated sociocultural and sociolinguistic theoretical framework informs a pedagogical approach where constructs like mediation, zone of proximal development, and interaction suggest using language as a social semiotic tool for science sense-making. Through the three metafunctions of language in SFL—ideational, interpersonal, textual—and the genre of science explanations, teachers use this integrated approach to intentionally plan for the targeted learning experiences in the *explore* phase to 'do science' and *explain* phase to 'talk science.' Since the coronavirus pandemic required a sudden mass movement from face-to-face instruction to remote instruction, it was also critical for this teacher educator to offer technology platforms and/or applications that would provide teachers of students with resources for planning the science *explore* phase. Thus, the approach offered here suggests the use of applications including but not limited to Padlet, nearpod, Kahoot, and PhET simulations to provide students with virtual hands-on practice to experience science learning. However, the same applications are also offered to teachers so that they are used for communication purposes using one genre commonly used by scientific communities—science explanations. Using this virtual pedagogical approach provides teachers with very intentional planning for conceptual and linguistic outcomes that together provides students with opportunities to mediate science learning, make sense of scientific phenomena, and engage in interaction through the use of science explanations. Use of the 5E instructional process, while always prioritizing the conceptual and linguistic outcomes of students, assists teachers in determining the scaffolding required in both content and language production to move students from actual to potential knowledge development levels as one way to be intentional about their zones of proximal development.

Implications for research suggest instructional interventions designed to measure second language learner conceptual and linguistic outcomes. Such interventions would inform intentional content and language teaching through measurement of fidelity of implementation. Interventions would measure student-intended content and language outcomes for CLD students. Additionally, instructional interventions would explore the effect of conceptual and linguistic scaffolding and their removal as students move from one knowledge development level to another. Lastly, interventions using this approach would help further inform the use of technology to enhance students' opportunities to explore science learning and communicate via discipline specific language use.

One limitation of this chapter is that the author centers only on one specific genre—explanations. Constructing arguments and the language skill of engaging argumentation not only requires the use of explanations, but also requires the use of persuasive language resources to persuade the scientific community and continue the construction of new scientific knowledge. In a classroom, students should also experience opportunities to engage in argumentation to experience different ways of knowing or epistemologies between them and their peers, but also ways to evaluate their own learning and refine their conceptual understanding of science phenomena. *Using Language as a Social Semiotic Tool in Virtual Science Instruction DOI: http://dx.doi.org/10.5772/intechopen.101814*


Preface

While great efforts are being made to reduce energy consumption, the world needs to further explore renewables like solar, wind, hydropower, geothermal, and even sustainable nuclear energy. However, due to high capital cost, these alternatives have not found wide application in industry. However, this is beginning to change with the emergence of scientific evidence that alternative sources of energy can help achieve sustainability in energy recovery (ER) processes. The case for other industries will follow the same argument especially since most of these heavy industries require enormous amounts of energy, derivable from fossil fuels oil and gas due to their resilience in offering likewise enormous motive power twenty-four hours a day. This book discusses sustainable ER development in our deliberate pursuit of energy independence in a world bedeviled by the ill effects of environmental degradation. In a world that needs energy, we should embrace the practice of utilizing ER systems in all their forms, natural and technological.

This book investigates ER in large industries and utilities throughout the world. In all aspects of heat exchanges, energy recoveries are involved, but the problem in all energy recoveries is that the percentage of energy recovered is not related to the total energy consumption in industry, organization, or household. It should be noted that among other objectives of studying ER one should take cognizance of the fact the recovered energy has these attributes: (1) it is quality energy because it is immediately useful without further processing depending on the point of collection, either through recuperators or economizers, whereby utilization is in preheating incoming air to a combustion chamber/ furnaces or in an AC/refrigeration system, which depends on the outside; (2) it becomes available energy, serving the purpose of extracting tangible heat (enthalpy) from the air, which is a two-component system for immediate use in effecting cooling on the area. The explanation here is that the wet air that contains water vapor after reaching its saturation vapor pressure undergoes the process of evaporation thereby cooling that point.

Chapter 1 pays special attention to the magnetocaloric effect (MCE) that is observed when magnetic systems are subjected to an external magnetic field. The authors use the derivative of Gibbs free energy to estimate the magnetic entropy change and the mean-field theory to sort out the spontaneous magnetization from the dependence of magnetic entropy change on magnetization vs. Gd systems. The obtained spontaneous magnetization values are in good agreement with those found from the extrapolation from the Arrott plots (H/M vs. M2). An excellent agreement has been found between the values estimated by Landau's theory and those obtained using the classical Maxwell relation. The intermetallic Gd3Ni2 and Gd3CoNi exhibit a large MCE manifested with a high entropic peak that can boost refrigerant capacity, which makes these alloys good candidates for magnetic refrigerators.

A micro-thermoelectric generator (TEG) possesses great potential for powering wireless Internet of Things (IoT) sensing systems due to its capability of harvesting thermal energy into usable electricity. Chapter 2 reviews the progress in recent studies on micro-TEG from material synthesis to device fabrication. Thermoelectric materials are synthesized by the electrochemical deposition method. Three kinds of high-performance thermoelectric materials, including thick bulk-like thermoelectric material, Pt nanoparticles embedded in a thermoelectric material, and Ni-doped thermoelectric material, are presented.

The growth of the semiconductor market and advancement of manufacturing technology have led to an increase in wafer size and highly integrated semiconductor devices. The temperature of the supplied cooling medium from the chiller that removes the heat produced in the semiconductor manufacturing process is required to be at a lower level because of the high integration. The Joule-Thomson cooling cycle, which uses a Mixed Refrigerant (MR) to produce the cooling medium at a level of −100°C required for the semiconductor process, has recently gained attention. Chapter 3 discusses this in detail. When an MR is used, the chiller's performance is heavily influenced by the composition and proportions of the refrigerant charged to the chiller system. Therefore, this chapter introduces a cooling cycle that uses an MR to achieve the required low temperature of −100°C in the semiconductor manufacturing process and provides the results.

Chapter 4 explains that the solar furnace supply doesn't make changes inside a material by using electric energy produced by a photovoltaic system that converts solar energy. The performances of a solar furnace used in various applications from industry are influenced by various factors. One of these factors imposes the acquisition of certain large densities of the radiant power and requires a geometric form of the concentrator. The most important research is made on the behavior of some metallic alloys at elevated temperatures, on some purifying materials, and on the achievement of some chemical synthesis. For manufacturing electrothermal furnaces, a series of specific materials are used that are necessary for the achievement of the furnace chamber (e.g., heating elements and measurement systems of the temperature).

Since the world is gradually drifting toward sustainable development, renewable energy technologies are gaining traction and gasification technology is one of many renewable energy technologies that have gained popularity in recent times. Gasification technology is one of three main (combustion and pyrolysis) thermochemical conversion pathways that can be used to recover energy from biomass materials. Chapter 5 presents an overview of gasification technology and discusses the different types of gasification systems that are commonly used today for the recovery of energy. The limitations of each type of gasifier in relation to performance and feedstock conversion are also discussed, including research priority areas that will allow for system optimization in terms of efficiency.

Chapter 6 proposes a novel, clean thermochemical process that harnesses thermal plasma technology to co-produce hydrogen and ammonia using a chemical looping process. The thermodynamic potential and feasibility of the process are demonstrated using a simulation of the system with aluminium and aluminium oxide as the oxygen and nitrogen carriers between the reactors. The effect of different operating parameters, such as feed ratio and temperature of the reactor, on the energetic performance

of the process is investigated. It is demonstrated that the process can operate at an approximate self-sustaining factor of 0.11 and an exergy partitioning fraction of up to 0.65. Integrating the process with solar photovoltaics shows a solar share of 32% without considering any battery storage units.

Finally, Chapter 7 provides an overview of energy efficiency in the mining industry with a particular focus on the role of fuel consumption in hauling operations in mining. Moreover, as the costliest aspect of surface mining with a significant environmental impact, diesel consumption is investigated in this chapter. This research seeks to develop an advanced data analytics model to estimate the energy efficiency of haul trucks used in surface mines, with the goal of lowering operating costs. The visualized results also clarify the general minimum areas in the plotted fuel consumption graphs. These areas potentially open a new window for researchers to develop optimization models to minimize haul truck fuel consumption in surface mines.

> **Petrica Vizureanu** "Gheorghe Asachi" Technical University, Iasi, Romania

Section 1

Heat Recovery

**1**

Section 1 Heat Recovery


**1. Introduction**

In today's world, the performance of business and corporates of a country plays a very important role in its position as a world leader. The per capita income, employment rate and other economic variables depend a lot upon the performance of business houses in that country. The stock price of a company fluctuates according to the performance of the business and the economy as a whole. The timing and the decision about buying and selling of stock depend upon the

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2018 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

stock price level. When an investor decides to invest in a stock he always looks for strong and growing companies, the value of the firm is reflected in the stock prices of that firm, and that is how an investor without any finance knowledge selects the stock-by-stock price movements.

In the present study, the attempt has been made to study the impact of select internal determinants and macroeconomic determinants of the share price of listed 26 nonfinancial companies in the Muscat Securities Market. A lot of work has been done on this topic, but most of the studies are based on establishing a relationship between dividend policy and stock prices. To the best of researcher's knowledge, this study is the pioneer study on the Oman capital market, based on stock price determinants of the companies from Muscat securities market. In the previous studies from GCC countries [4–6] and studies from other countries, authors have not studied any specific sector for share price determinants. Another contribution of this study is that it is exclusively based on nonfinancial companies. The nature of balance sheet in financial companies varies from nonfinancial companies in terms of leverage, current assets and fixed assets composition. Therefore, to study the impact of company-specific determinants on share prices a separate sample of financial and nonfinancial companies would yield better results rather than studying the mix of all types of

Stock Price Determinants: Empirical Evidence from Muscat Securities Market, Oman

http://dx.doi.org/10.5772/intechopen.77343

23

The whole chapter is organized into five sections including introduction. Section 2 describes the literature review. Section 3 discusses the methodology and data. Section 4 presents the empirical results and its discussion thereof. Section 5 presents conclusion with policy implications.

Collins [7] was the pioneering work on determinants of share prices based on the US market, the findings of the chapter recognized book value of equity, dividend, net profit and operat-

Nirmala et al. [8] used fully modified least square regression model on panel data of 37 Indian companies from 2000 to 2009. The study identified price earnings ratio, leverage and dividend per share as the major determinants of share prices. In the Indian context, this study was also conducted by Tandon and Malhotra [9]; they tried to identify determinants of stock prices for 100 companies listed in National Stock Exchange (NSE) using linear regression model from 2007 to 2012. The results indicated that firms' book value, earning per share and price-earnings ratio have a significant positive association with firm's stock price, while dividend yield has a significant inverse association with the market price of the

Malhotra and Prakash [10] studied the determinants of stock prices of Indian companies during 1990–1999 with the help of correlation and regression analysis. Book value per share, dividend per share, market to book ratio and PE ratio emerged as the significant determinants

Oseni [11] studied the impact of earnings per share (EPS), oil price, dividend per share (DPS), GDP, foreign exchange rate and interest rates on share prices of 130 companies from the Nigerian stock exchange. The study revealed a strong positive correlation between stock

ing cash flows as the significant factors affecting share prices.

prices and EPS, oil price, dividend per share and GDP.

companies.

firm's stock.

of the share prices.

**2. Review of literature**

One of the key sources of financing for the listed firms is the stock issue, and for successful stock issue, firms need to have a strong track record in the stock market. There are various stakeholders to the business, like shareholders, creditors, customers, employees, and government. The rising stock price is an indicator of good management and satisfaction for all the stakeholders. There are company-specific and market-related determinants of stock prices; in literature, many theories are available that explain the movement in the stock prices.

One of the most significant theories is the Efficient Market Hypothesis (EMH), which is based on the assumption that rational investors in the market react to the available information like company fundamentals and other important declaration about the company to decide on the stock buying or selling. If they feel that the information is positive, then they retain the shares if already bought or buy the one which was not purchased earlier and vice versa. The action of buying and selling stocks by the investors is responsible for changes in stock price. There are three forms of EMH—weak, semi-strong and strong form—and they vary regarding available information for public and investors. Another theory 'Random walk' states that stock prices are random and cannot be predicted by any means. This theory has been empirically tested many times and proved by the researchers. A random walk is consistent with EMH, as the flow of information is random which helps investors in reassessing the stock price.

The third theory 'Behavioral Finance Theory' is very different from the random walk and the EMH theories. This theory states that investors do not behave rationally rather they invest by psychological and behavioral factors; for example, they will invest in the stock if the stock price is increasing even if there are no significant changes in the company fundamentals.

Gordon [1] revealed that dividend payment and growth rate of the company have an impact on the intrinsic value of shares. The model was based on the assumption of constant growth in dividends which was one of the weaknesses of the model, but still, it is the highly used model to calculate the intrinsic value of the stock. This model claims that expected dividend and growth rate of the company are positive determinants of stock prices.

A considerable amount of research has been done to find out internal determinants of share price changes of companies, some of the common factors found are dividend yield, total assets, earning per share, capital structure and book value per share. Apart from internal variables, macroeconomic variables also have an impact on share prices that have been discussed by Roll and Ross [2] in his arbitrage pricing theory (APT), a framework for pricing securities for investors. According to Ross, common macroeconomic factors affecting share prices were unexpected changes in inflation, GDP and changes in the yield curve. APT model is flexible as investors can select other factors also depending on the market like for oil exporting and importing countries oil price can be an important factor affecting security prices. Mukherjee and Naka [3] supported the APT theory by confirming the impact of economic variables on the stock returns; they argued that changes in economic variables affect dividend payments and discount rates and thus have an impact on share prices as well.

In the present study, the attempt has been made to study the impact of select internal determinants and macroeconomic determinants of the share price of listed 26 nonfinancial companies in the Muscat Securities Market. A lot of work has been done on this topic, but most of the studies are based on establishing a relationship between dividend policy and stock prices. To the best of researcher's knowledge, this study is the pioneer study on the Oman capital market, based on stock price determinants of the companies from Muscat securities market. In the previous studies from GCC countries [4–6] and studies from other countries, authors have not studied any specific sector for share price determinants. Another contribution of this study is that it is exclusively based on nonfinancial companies. The nature of balance sheet in financial companies varies from nonfinancial companies in terms of leverage, current assets and fixed assets composition. Therefore, to study the impact of company-specific determinants on share prices a separate sample of financial and nonfinancial companies would yield better results rather than studying the mix of all types of companies.

The whole chapter is organized into five sections including introduction. Section 2 describes the literature review. Section 3 discusses the methodology and data. Section 4 presents the empirical results and its discussion thereof. Section 5 presents conclusion with policy implications.


**8. Appendix II (Symbols)**

254 Acoustic Waves – From Microdevices to Helioseismology

The depth of penetration of a shear wave (δ) in a Newtonian medium is given by the

1

1

*m m*

arctan

 η (2)

 ω

1/4 2

() 2

*n n m nm m Sin C C*

*Chromosome:* Each individual has a number of chromosomes that represent each parameter

*Genes:* Each chromosome contains a fixed number of genes, the number of genes per chromosome determine the resolution of the total solution. The number of genes per chromosome is mostly determined by the broadness of the range in which each

*Fitness:* Every individual has to be weighed according to its fitness. The individual fitness value determines its survival and breeding probability. A higher fitness individual has

As seen in fig. 11, the biological process consist of a piezoelectric layer (MTSM sensor) and a non-piezoelectric biological layer. In this model, each layer of load can be represented as a

Fig. 11. Mason model representation of non-piezoelectric layers loaded on piezoelectric plate

= − − +

2 2

ω η

ρ

**7. Appendix I**

equation shown below:

n = harmonic number

chromosome lies.

higher probability of survival.

T-network of impedances.

**C. Mason's transmission line model**

**A. The depth of penetration of a shear wave (δ)**

ω

*n*

**B. Basic terminologies of a genetic algorithm**

(i.e. variables to be determined) of the problem.

*Individual:* A solution to the problem is called an individual. *Population:* The total number of solutions is called population.

δ

ρm = density of medium (kg/m3), ηm = viscosity of medium (kg/m.s), Cm = stiffness of medium (N/m2), ω = angular frequency (rad/s) and

F1 = input force (N) F2 = output force (N) v1 = input particle velocity (m/s) v2 = output particle velocity (m/s) A = area of active electrode of MTSM (m2) k = propagation constant (m-1) d = thickness (m) Z = acoustic impedance (acoustic ohm) I = current (C) C0 = static capacitance of MTSM (F) φ: transformer ratio


**1. Introduction**

The linkage between caribou and the aboriginal people in the North America has existed for thousands of years. Caribou have played a critical role in the economy, culture, and way of life of the aboriginal people (Hall, 1989; Madsen, 2001). Currently, there are 60 major migratary tundra caribou herds circum-arctic, of which 30 are located in North America, including the Porcupine caribou herd in northern Yukon, Canada and northern Alaska, USA (Russell et al., 1992; Russell et al., 1993; Russell & McNeil, 2002; Russell et al., 2002; Griffith et al., 2002). The Porcupine caribou herd has been at the centre of debate between wildlife habitat conservation and industrial development in the Arctic because of the potential oil drilling in the Arctic National Wildlife Refuge (ANWR) 1002 area, which happens to largely overlap with the calving ground of the Porcupine caribou herd (Griffith et al., 2002; Kaiser, 2002; National Research Council, 2003; Heuer, 2006).

One of the objectives of the Canadian International Polar Year (IPY) project entitled "Climate Change Impacts on Canadian Arctic Tundra Ecosystems (CiCAT): Interdisciplinary and Multi-scale Assessments" was to assess the impact of climate change on caribou habitats over Canada's north, in close collaboration with the CircumArctic Ranfiger Monitoring and Assessment network (CARMA) (http://www.rangifer.net /carma/). Because of the vastness and remoteness of the arctic landmass, inherent logistic difficulty, and high cost of conducting field measurements, an approach that is solely based on field inventory is clearly impractical for monitoring and assessing the impact of climate on caribou habitats. Satellite remote sensing can monitor land surfaces from space repeatedly and consistently over large areas. Therefore, remote sensing provides a powerful tool for monitoring and assessing the impact of climate on caribou habitats, when calibrated and validated against the field measurements and other independent data.

In this study, we report the development of baseline maps of aboveground and foliage biomass over the Porcupine caribou habitat in northern Yukon and Alaska, using Landsat and JERS-1/SAR data. Specifically, we will (1) describe aboveground and foliage biomass measurement, (2) establish and validate relationships between measurements and remote sensing indices, and (3) map aboveground and foliage biomass for the Porcupine caribou habitat.

Mapping Aboveground and Foliage Biomass Over the Porcupine Caribou

of the trees were then calculated on basis of allometric equations.

weight.

laboratory.

Habitat in Northern Yukon and Alaska Using Landsat and JERS-1/SAR Data 233

with *DBH* is in centimeters and plot radius is in meters, *PRF* is in m cm-1. A tree is included or "in" if *DBHi* > *ri/PRF*, and excluded or "out" otherwise. A difficulty may arise as whether to include or exclude a tree if it's at the edge, namely, *DBHi* ≈ *ri/PRF*. If this is the case, the distance from the plot centre to the tree is measured. Using the tree's *DBH* and the appropriate PRF, this distance can then be compared to the radius of the plot as calculated by equation 1, and the tree place "in" or "out" of the plot after-the-fact. The measurements included tree height, diameter at breast height (*DBH*), and stand density. The heights of trees are recorded using a laser height measurement instrument (Impulse Forest Pro, Lasertech, Clarkston, MI, USA). Trees for height measurement are selected on basis of the point plot scheme. The value of *DBH* was measured using a tape. The stocking and biomass

If tree regeneration was present, we measured the biomass of the seedlings using a fixed circular plot of radius of 3.99 m. The measurements included counting the number of stems per tree species, selecting an average-sized seedling to estimate its ground stem diameter, height, and sampling one or two average-sized seedling to measure its fresh and oven-dry

For the understory layers, namely, high shrub, low shrub, herbs/graminoids, moss, and lichen, we harvested samples at five 1 m × 1 m plots to measure the total aboveground biomass: four at four directions and one random (Fig. 2). All the aboveground biomass within the plots were cut and collected into plastic bags and their green biomass weighed. Out of the five plots, we selected one representative plot to conduct an intensive sampling. For this plot, we measured the average height, visually estimate the ground cover percentage, and then cut and weighed the fresh biomass, sequentially, for tall shrub, low shrubs, herbs/graminoids, moss, and lichen. The ratio of green to oven-dry biomass was measured by bringing a sample of the aboveground biomass from the plot back to

If a site had no trees, then we applied the aforementioned understory procedure. Note that the plot number and design of a specific site were determined on basis of site conditions: the more heterogeneous and sparse the vegetation is at a site, the more plots are needed (Chen et al., 2009b; Chen et al., 2010b). The procedure was modified for tall shrubs if the tall shrubs (higher than 50 cm) were clustered instead of homogeneous distribution. Our field experience indicated that it was often the case for tall shrubs. In this case, we measured the biomass of tall shrubs using a fixed circular plot of radius = 3.99 m. The measurements included identifying shrub species, counting number of clusters of shrub in the plot, and selecting two average-sized clusters of shrub for more extensive sampling. All aboveground biomass of the two clusters of shrub were cut and weighed for total green biomass. A fraction of the biomass was brought back to measure the ratio of oven-dry to fresh weight. If there are more than one tall shrub species, we repeated the measurements for each of them.

The procedure for low shrub, herbs/graminoids, moss, and lichen remain the same.

For foliage biomass measurement during the summers of 2006 and 2008, we selected only non-treed sites. At each sites, five 1 m × 1 m plots were sampled (Fig. 3). Fig. 3 shows a photograph of the field sampling at a coastal plain site in the Ivvavik National Park during the summer of 2008. At each plot, all plants were harvested, sorted into dead and live, different species, and leaves and stem, and recorded for their fresh weights. A fraction of the harvested biomass for all components were brought back to the laboratory, oven-dried, and

*PRF r / DBH or r PRF DBH i ii i* (1)