$\Gamma$-GUARDING OF ORTHOGONAL POLYGONS

Abstract

Guarding of an environment by cameras or guards is a longstanding problem in computational geometry. In this paper, we introduce a new type of guarding problems called Γ-guarding using staircase visibility. A point inside an orthogonal environment is said to be staircase visible for a given camera if there exists a staircase path from camera to the point so that it is completely contained in the environment. In this model, we place a small number of guards inside an orthogonal polygon so that each point of polygon is staircase visible through at least four directions. We present an algorithm for Γ-guarding an arbitrary orthogonal polygon that yields an upper bound for the number of guards that protect an orthogonal polygon through four directions.

Recent advances in nanomaterials‐based optical sensors for detection of various biomarkers (inorganic species, organic and biomolecules)

“…As a result of surface plasmon resonances (SPRs), metal nanostructures can generate a strong electric field near them, or greatly enhance the scattering response by accelerating the rate of light scattering from such nanostructured material, resulting in the analysis of molecular vibrations with greater and better signals. To boost the Raman scattering signal SERS generally uses silver (Ag), Au, noble metal and copper NPs [ 49 ] as shown in Figure 3. Using in situ production of AgNPs on the surface of TA modified MIL‐101, an effective SERS substrate was developed (Fe).…”