3-D Coverage Path Planning for Underwater Terrain Mapping

This thesis presents an autonomous approach of 3-D coverage of underwater terrain using multi-level coverage trees. An autonomous underwater vehicle (AUV) equipped with multi-beam sonar sensors, Doppler velocity log (DVL) and inertial measurement unit (IMU) sensors is used to achieve this goal. The underwater 3-D search space is represented by a multi-level coverage tree which is generated online based on the obstacle information collected by the AUV. The nodes of the tree correspond to safe sub-areas for AUV navigation which are identified based on obstacle density in neighborhood of free cells. Standard tree traversal strategies like depth-first-search (DFS) and breath-first-search (BFS) are then used for visiting all the nodes of the tree thus securing complete coverage of the 3-D space. The terrain data collected by the AUV during tree coverage is used offline for the 3-D reconstruction of seabed using alpha shapes algorithm. The performance of this method is validated using a high-fidelity underwater simulator UWSim based on Robot Operating System (ROS). The simulations show that the proposed methodology achieves complete coverage and accurate reconstruction of 3-D underwater terrain

Type 1_A angiotensin II receptor abundance.

<p>Semiquantitative immunoblotting of kidney protein prepared from inner medulla. Immunoblot was reacted with anti-AT1R revealing a single band at ~ 43 kDa (<i>A-E</i>). Data are presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116501#pone.0116501.t007" target="_blank">Table 7</a>. (<i>A</i> and <i>B</i>) Analysis revealed significantly decreased AT1R expression in HF and L-HF vs. Sham and vs. L-Sham, respectively. AT1R expression was comparable in Sham and L-Sham. <i>C</i>) When compared with HF and L-HF, AT1R protein expression was decreased in the L-HF+d rats, whereas levels between HF and L-HF were comparable. <i>D</i>) Decreased expression of AT1R was observed in L-HF+d rats when compared with L-Sham and L-Sham+d, whereas AT1R levels between L-Sham and L-Sham+d were comparable, as also presented in <i>E</i>). <i>E</i>) AT1R protein expression was comparable between Sham, L-Sham and L-Sham+d. Each column represents the mean ± SE. Solid white, Sham; solid light grey, HF; line pattern, L-Sham; solid dark grey, L-HF; solid black, L-HF+d; dotted pattern, L-Sham+d. *<i>P <</i> 0.05 vs. Sham, # <i>P <</i> 0.05 vs. HF, † <i>P <</i> 0.05 vs. L-HF+d.</p

AQP4 abundance.

<p>Semiquantitative immunoblotting of kidney protein prepared from inner medulla. Immunoblot was reacted with anti-AQP4 antibody and reveals a single ~ 34.5 kDa AQP4-band (<i>A-E</i>). Data are presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116501#pone.0116501.t010" target="_blank">Table 10</a>. (<i>A-B</i>) Densitometric analysis revealed significantly increased AQP4 protein levels of HF, L-HF and L-Sham vs. Sham. The increase in HF, L-HF and L-Sham was comparable. In contrast, AQP4 protein levels in L-HF+d decreased vs. HF and L-HF in <i>C</i>) and vs. L-Sham and L-Sham+d in <i>D</i>). No difference was observed between L-Sham and L-Sham+d, as also presented in <i>E</i>). <i>E</i>) AQP4 protein levels in L-Sham+d and L-Sham were increased compared with Sham. No difference was observed between L-Sham and L-Sham+d. Each column represents the mean ± SE. Solid white, Sham; solid light grey, HF; line pattern, L-Sham; solid dark grey, L-HF; solid black, L-HF+d; dotted pattern, L-Sham+d. *<i>P <</i> 0.05 vs. Sham, #<i>P <</i> 0.05 vs. HF, † <i>P <</i> 0.05 vs. L-HF+d, ‡ <i>P <</i> 0.05 vs. L-Sham.</p

Inner medullary expression of AQP2 and p-AQP2.

<p>Values are expressed as means ± SE. AQP2, aquaporin-2;</p><p>p-AQP2, p(Ser256)-aquaporin-2;</p><p>n, number of rats.</p><p>*<i>P <</i> 0.05 vs. Sham</p><p># <i>P <</i> 0.05 vs. HF</p><p>† <i>P <</i> 0.05 vs. L-HF+d</p><p>‡ <i>P <</i> 0.05 vs. L-Sham</p><p>♣ <i>P <</i> 0.05 vs. L-Sham+d. Values are expressed as means ± SE.</p><p>Inner medullary expression of AQP2 and p-AQP2.</p

Inner medullary expression of AQP1.

<p>Values are expressed as means ± SE. AQP1, aquaporin-1;</p><p>n, number of rats. L-Sham+d.</p><p>*<i>P <</i> 0.05 vs. Sham</p><p>¤ <i>P <</i> 0.05 vs. L-HF.</p><p>Inner medullary expression of AQP1.</p

Inner medullary expression of the Gsα subunit.

<p>Values are expressed as means ± SE. Gsα, Gsα subunit;</p><p>n, number of rats.</p><p>*<i>P <</i> 0.05 vs. Sham</p><p># <i>P <</i> 0.05 vs. HF</p><p>† <i>P <</i> 0.05 vs. L-HF+d</p><p>‡ <i>P <</i> 0.05 vs. L-Sham</p><p>♣ <i>P <</i> 0.05 vs. L-Sham+d.</p><p>Inner medullary expression of the Gsα subunit.</p

Inner medullary expression of AQP3 and Na-K-ATPase.

<p>Values are expressed as means ± SE. AQP3, aquaporin-3;</p><p>Na-K-ATPase, Na-K-ATPase;</p><p>n, number of rats.</p><p># <i>P</i> < 0.05 vs. HF</p><p>‡ <i>P <</i> 0.05 vs. L-Sham.</p><p>Inner medullary expression of AQP3 and Na-K-ATPase.</p

AQP2 and p-AQP2 abundance.

<p>Semiquantitative immunoblotting of kidney protein prepared from inner medulla. Immunoblot was reacted with anti-AQP2 (<i>A-E</i>) and AQP2 phosphorylated at Ser256 (p-AQP2) (<i>F-J</i>) antibody. Both antibodies reveal specific 29 kDa and 35–50 kDa bands. Data are presented in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0116501#pone.0116501.t004" target="_blank">Table 4</a>. Densitometric analysis revealed unchanged AQP2 and p-AQP2 protein levels in HF and L-HF vs. Sham 17 days after MI. Neither sodium restriction nor DDAVP infusion increased AQP2 and p-AQP2 abundance in HF as otherwise observed in L-Sham+d (<i>A</i>, <i>B</i> and <i>F</i>, <i>G</i>). Consistently, L-HF+d revealed decreased AQP2 and p-AQP2 abundance to L-HF levels vs. L-Sham and HF (<i>C</i>, <i>D</i> and <i>H</i>, <i>I</i>). Furthermore, AQP2 and p-AQP2 expression was decreased in L-Sham rats compared with Sham, HF, and L-Sham+d (<i>A</i>, <i>B</i>, <i>E</i> and <i>F</i>, <i>G</i>, <i>J</i>, respectively). In contrast, no difference was observed in L-Sham+d was observed vs. Sham (<i>E</i> and <i>J</i>). Each column represents the mean ± SE. Each column represents the mean ± SE. Solid white, Sham; solid light grey, HF; line pattern, L-Sham; solid dark grey, L-HF; solid black, L-HF+d; dotted pattern, L-Sham+d. *<i>P <</i> 0.05 vs. Sham, # <i>P <</i> 0.05 vs. HF, † <i>P <</i> 0.05 vs. L-HF+d, ‡ <i>P <</i> 0.05 vs. L-Sham, ♣ <i>P <</i> 0.05 vs. L-Sham+d.</p

Inner medullary expression of the V2 vasopressin receptor.

<p>Values are expressed as means ± SE. V2R, V2 vasopressin receptor;</p><p>n, number of rats.</p><p>*<i>P <</i> 0.05 vs. Sham</p><p># <i>P <</i> 0.05 vs. HF</p><p>† <i>P <</i> 0.05 vs. L-HF+d.</p><p>Inner medullary expression of the V2 vasopressin receptor.</p

AQP2 and p-AQP2 IMCD localization.

<p>Immunoperoxidase microscopy of AQP2 and p-AQP2 in the inner medulla. Sections were incubated with affinity-purified anti-AQP2 (<i>A – E</i>) or affinity-purified anti-p-AQP2 antibody (<i>F</i> – <i>J</i>), and labeling was visualized using peroxidase-conjugated secondary antibody. <i>A – B</i>: In standard salt diet Sham rats AQP2 and p-AQP2 labeling is present at the apical and intracellular domains (arrows). <i>C – F</i>: AQP2 and p-AQP2 stainings from L-Sham and L-Sham+d rats were mainly situated in apical domains with weak intracellular labeling. <i>G – L</i>: In contrast, all HF groups demonstrated strong apical immunoperoxidase labeling of AQP2 and p-AQP2 with virtually no staining in intracellular domains. Magnification x 630.</p