Most applications of underwater acoustic sensor networks (UASNs) rely upon reliable location information nodes. However, the harsh environment makes localization more challenging as compared to terrestrial networks. This paper is concerned with a issue for UASNs, subject clock asynchronization and node mobility. A hybrid architecture including autonomous vehicles (AUVs), active passive nodes designed, where AUVs act anchor provide In order eliminate effect asynchronous clocks compensate...

Underwater sensor networks (USNs) have been identifies as a promising technology to monitor and explore the underwater environment. Most applications of USNs demand reliable accurate localization for nodes. However, mobility clock asynchronous characteristics on nodes make it challenging achieve localization. In this paper, we are concerned with AUV assisted problem USNs, where AUVs run mobile reference points. A tracking variance threshold is set determine occasion process. The node need be...

In this paper, we develop a simple and efficient formation control framework for heterogeneous multi-agent systems under min-weighted persistent graph. As the ability of each agent may be different, architecture agents is considered to heterogeneous. To reduce communication complexity keeping connectivity agents, topology optimisation scheme proposed, which based on According directed acyclic graph (DAG) constructed reflect signal flow relation then corresponding protocol designed by using...

In this paper, we develop a simple and efficient formation control framework for heterogeneous multi-agent systems under min-weighted persistent graph. As the ability of each agent may be different, architecture agents is considered to heterogeneous. To reduce communication complexity keeping connectivity agents, topology optimisation scheme proposed, which based on According directed acyclic graph (DAG) constructed reflect signal flow relation then corresponding protocol designed by using...

Most applications of underwater acoustic sensor networks (UASNs) rely upon accurate location information target. However, the asynchronous clock and noise measurement characteristics environment make target localization more challenging as compared to terrestrial networks. In this paper, we design an algorithm for UASNs, where synchronous assumption is relaxed. order reduce influence measurement, a consensus-based unscented Kalman filtering (UKF) proposed obtain Finally, simulation results...

Based on measuring technique of ordinary sensor rotation rate and torque, this article mainly studied the sensing element CMF (Coriolis Mass-Flow Meter), designed for prototype an IDDSRT (Integrated Direct Digital Sensor Rotation Rate Torque) that consists torsion-bar spring, fluted disc, photoelectric device. The measures with high-frequency pulse. This design reduces factors affect measuring, completely realizes non-contact digital measurement, greatly improves anti-jamming ability...

Abstract Stick-slip vibration is likely to occur while drilling in hard formation and soft-hard interbedded formation, especially when PDC bit used, which further results lower ROP short footage. In this study, Gyro Shock-damping Tool optimization design were tested reduce the stick-slip lengthen life granite buried hill formation. Main parameters of include: 8 blades, parabolic profile, Trident IV PDC, 10mm, 13mm cutter, totally 90 cutters, back rake 19°-23°, double row cutter (back...

Abstract With many advantages of protecting reservoir, increasing drilling speed and high capacity in carrying cuttings, foam is suitable for through the aquifer natural fractured formation, has been developed fast since 1990s. However, change physical properties along wellbore, flowing state annulus complex. Therefore, it difficult to optimize design hydraulic parameters drilling. In order solve this problem, mathematical model foam-cutting developed. addition, sensitivity analysis...

In the Yingxiongling Area of Qaidam Basin, formation pressure system is complicated in vertical, and high mechanism has not been made clear, which brought a great challenge to drilling work. To solve this problem, study, an advanced method with acoustic velocity-density crossplot used analyze abnormal Basin. The results have shown that mainly caused by under-compaction, concentrated layers form N22 E32. According mechanism, Eaton Fan simple selected calculate typical high-pressure wells By...