The IEEE 802.15.4 standard has attracted time-critical applications in wireless sensor networks (WSNs) because of its beaconenabled mode and guaranteed time slots (GTSs). However, the GTS management scheme’s built-in security mechanisms still leave the 802.15.4 MAC vulnerable to attacks. Further, the existing techniques in the literature for securing 802.15.4 either focus on non beacon-enabled ...

Stanford's Space Systems Development Laboratory is developing methods for automated spacecraft health operations. Such operations greatly reduce the need for ground-space communication links and full-time operators. However, new questions emerge about how to supply operators with the spacecraft information that is no longer available. One solution is to introduce a low-bandwidth health beacon a...

Spatial and temporal control of molecular mechanisms can be achieved using photolabile bonds that connect biomolecules to protective caging groups, which can be cleaved upon irradiation of a specific wavelength, releasing the biomolecule ready-to-use. Here we apply and improve a previously reported strategy to tightly control in vitro transcription reactions. The strategy involves two caging mo...

IEEE 802.15.4 provides beacon enabled and non-beacon enabled modes. Beacon enabled mode is generally used for energy efficiency. However, the main problem of beacon enabled mode is the fixed superframe structure that leads to inefficient transmission in dynamic traffic conditions. Moreover, 802.15.4 does not provide differential service according to traffic types. In this paper, we propose a Di...

A beacon is a point-like object that can be enabled to exert a magnetic pull on other point-like objects in space. Those objects then move towards the beacon in a greedy fashion until they are either stuck at an obstacle or reach the beacon’s location. Beacons placed inside polyhedra can be used to route point-like objects from one location to another. The notion of beacon-based routing was int...

We examine a protocol πbeacon that outputs unpredictable and publicly verifiable randomness, meaning that the output is unknown at the time that πbeacon starts, yet everyone can verify that the output is close to uniform after πbeacon terminates. We show that πbeacon can be instantiated via Bitcoin under sensible assumptions; in particular we consider an adversary with an arbitrarily large init...

This paper presents a mechanism that improves the energy efficiency of PSM (Power Saving Mechanism) specified for DCF (Distributed Coordination Function) in IEEE 802.11. In PSM, time is divided into beacon intervals. At the start of each beacon interval, every node stays awake for a duration, called the ATIM Window. During the ATIM window, nodes exchange control packets to determine whether the...

A rapid DNA analysis has been developed based on a fluorescence intensity change of a molecular beacon in a PDMS microfluidic channel. Recently, we reported a new analytical method of DNA hybridization involving a PDMS microfluidic sensor using fluorescence energy transfer (FRET). However, there are some limitations in its application to real DNA samples because the target DNA must be labelled ...

Beacon scheduling is considered to be one of the most significant challenges for energy-efficient Low-Rate Wireless Personal Area Network (LR-WPAN) multi-hop networks. The emerging new standard, IEEE802.15.4e, contains a distributed beacon scheduling functionality that utilizes a specific bitmap and multi-superframe structure. However, this new standard does not provide a critical recipe for su...

This work investigates into the design of sink location propagation in wireless sensor network with mobile sink. In our proposed work, few sensor nodes are assigning a role to propagate the sink location information to the remaining nodes. We refer such nodes as beacon nodes (BNs). We design a distributed algorithm to select BNs. The selection of BNs depends on their sensor node degree. To ensu...