Separation of distributed coordination and control for programming reliable robotics

A robot's code needs to sense the environment, control the hardware, and communicate with other robots. Current programming languages do not provide the necessary hardware platform-independent abstractions, and therefore, developing robot applications require detailed knowledge of signal processing, control, path planning, network protocols, and various platform-specific details. Further, porting applications across hardware platforms becomes tedious. With the aim of separating these hardware dependent and independent concerns, we have developed Koord: a domain specific language for distributed robotics. Koord abstracts platform-specific functions for sensing, communication, and low-level control. Koord makes the platform-independent control and coordination code portable and modularly verifiable. It raises the level of abstraction in programming by providing distributed shared memory for coordination and port interfaces for sensing and control. We have developed the formal executable semantics of Koord in the K framework. With this symbolic execution engine, we can identify proof obligations for gaining high assurance from Koord applications. Koord is deployed on CyPhyHouse---a toolchain that aims to provide programming, debugging, and deployment benefits for distributed mobile robotic applications. The modular, platform-independent middleware of CyPhyHouse implements these functionalities using standard algorithms for path planning (RRT), control (MPC), mutual exclusion, etc. A high-fidelity, scalable, multi-threaded simulator for Koord applications is developed to simulate the same application code for dozens of heterogeneous agents. The same compiled code can also be deployed on heterogeneous mobile platforms. This thesis outlines the design, implementation and formalization of the Koord language and the main components of CyPhyHouse that it is deployed on

QoS Provisioning of QoS in Wireless Networks

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Revelation of Varying Coordination Modes and Noninnocence of Deprotonated 2,2′-Bipyridine-3,3′-diol in {Os(bpy)₂} Frameworks

The reaction of 2,2′-bipyridine-3,3′-diol (H₂L) and <i>cis</i>-Os^II(bpy)₂­Cl₂ (bpy = 2,2′-bipyridine) results in isomeric forms of [Os^II(bpy)₂(HL^–)]­ClO₄, [<b>1</b>]­ClO₄ and [<b>2</b>]­ClO₄, because of the varying binding modes of partially deprotonated HL^–. The identities of isomeric [<b>1</b>]­ClO₄ and [<b>2</b>]­ClO₄ have been authenticated by their single crystal X-ray structures. The ambidentate HL^– in [<b>2</b>]­ClO₄ develops the usual N,N bonded five-membered chelate with a strong O–H···O hydrogen bonded situation (O–H···O angle: 160.78°) at its back face. The isomer [<b>1</b>]­ClO₄ however represents the monoanionic O^–,N coordinating mode of HL^–, leading to a six-membered chelate with the moderately strong O–H···N hydrogen bonding interaction (O–H···N angle: 148.87°) at its backbone. The isomeric [<b>1</b>]­ClO₄ and [<b>2</b>]­ClO₄ also exhibit distinctive spectral, electrochemical, electronic structural, and hydrogen bonding features. The p<i>K</i>_a values for [<b>1</b>]­ClO₄ and [<b>2</b>]­ClO₄ have been estimated to be 0.73 and <0.2, respectively, thereby revealing the varying hydrogen bonding interaction profiles of O–H···N and O–H···O involving the coordinated HL^–. The O–H···O group of HL^– in <b>2</b>⁺ remains invariant in the basic region (pH 7–12), while deprotonation of O–H···N group of HL^– in <b>1</b>⁺ estimates the p<i>K</i>_b value of 11.55. This indeed has facilitated the activation of the exposed O–H···N function in [<b>1</b>]­ClO₄ by the second {Os^II(bpy)₂} unit to yield the L^2– bridged [(bpy)₂Os^II(μ-L^2–)­Os^II(bpy)₂]­(ClO₄)₂ ([<b>3</b>]­(ClO₄)₂). However, the O–H···O function in [<b>2</b>]­ClO₄ fails to react with {Os^II(bpy)₂}. The crystal structure of [<b>3</b>]­(ClO₄)₂ establishes the symmetric N,O^–/O^–,N bridging mode of L^2–. On the other hand, the doubly deprotonated L′^2– (H₂L′ = 2,2′-biphenol) generates structurally characterized twisted seven-membered O^–,O^– bonded chelate (torsion angle >50°) in paramagnetic [Os^III(bpy)₂­(L′^2–)]­ClO₄ ([<b>4</b>]­ClO₄). The electronic structural aspects of the complexes reveal the noninnocent potential of the coordinated HL^–, L^2–, and L′^2–. The <i>K</i>_c value of 49 for <b>3</b>³⁺ reveals a class I mixed-valent Os^IIOs^III state

Significant Influence of Coligands Toward Varying Coordination Modes of 2,2′-Bipyridine-3,3′-diol in Ruthenium Complexes

The varying coordination modes of the ambidentate ligand 2,2′-bipyridine-3,3′-diol (H₂L) in a set of ruthenium complexes were demonstrated with special reference to the electronic features of the coligands, including σ-donating acac^– (= acetylacetonate) in Ru^III(acac)₂(HL^–) (<b>1</b>), strongly π-accepting pap (= 2-phenylazopyridine) in Ru^II(pap)₂(L^2–) (<b>2</b>)/[(pap)₂Ru^II(μ-L^2–)­Ru^II­(pap)₂]­(ClO₄)₂ ([<b>4</b>]­(ClO₄)₂), and reported moderately π-accepting bpy (= 2,2′-bypiridine) in [Ru^II(bpy)₂­(HL^–)]­PF₆ ([<b>5</b>]­PF₆)/[(bpy)₂Ru­(μ-L^2–)­Ru­(bpy)₂]­(PF₆)₂ ([<b>7</b>]­(PF₆)₂). The single-crystal X-ray structures reveal that, in paramagnetic and electron paramagnetic resonance active <b>1</b> and reported diamagnetic [<b>5</b>]­PF₆, nearly planar monoanionic HL^– coordinates to the metal ion via the <i>N</i>,<i>N</i> donors forming a five-membered chelate ring with hydrogen-bonded O–H···O function at the backbone of the ligand framework, as has also been reported in other metal complexes. However, structurally characterized diamagnetic <b>2</b> represents O^–,O^– bonded seven-membered chelate of fully deprotonated but twisted L^2–. The nonplanarity of the coordinated L^2– in <b>2</b> does not permit the second metal fragment {Ru­(pap)₂} or {Ru­(bpy)₂} or {Ru­(acac)₂} to bind with the available N,N donors at the back face of L^2–. Further, the deprotonated form of the model ligand 2,2′-biphenol (H₂L′) yields Ru^II(pap)₂(L′^2–) (<b>3</b>); its crystal structure establishes the expected O^–,O^– bonded seven-membered chelate of nonplanar L′^2– as in reported Ru^II(bpy)₂(L′^2–) (<b>6</b>), although {Ru­(acac)₂} metal precursor altogether fails to react with H₂L′. All attempts to make diruthenium complex from {Ru­(acac)₂} and H₂L failed; however, the corresponding {Ru­(pap)₂²⁺} derived dimeric [<b>4</b>]­(ClO₄)₂ was structurally characterized. It establishes the symmetric N,O^–/N,O^– bridging mode of nonplanar L^2– as in reported [<b>7</b>]­(PF₆)₂. Besides structural and spectroscopic characterization of the newly developed complexes, the ligand (HL^–, L^2–, L′^2–, pap)-, metal-, or mixed metal–ligand-based accessible redox processes in <b>1</b>^<i>n</i> (<i>n</i> = +2, +1, 0, −1), <b>2</b>^<i>n</i>/<b>3</b>^<i>n</i> (<i>n</i> = +2, +1, 0, −1, −2), and <b>4</b>^<i>n</i> (<i>n</i> = +4, +3, +2, +1, 0, −1) were analyzed in conjunction with density functional theory calculations