Abstract This paper addresses denial of service vulnerabilities (DOS) in 802.11 wireless LANs that arise from the 802.11 distributed coordination function (DCF). We demonstrate that the DCF is vulnerable to equivalent DOS attacks at both the MAC and PHY layers. Denial of service attacks against the DCF are easily staged by a single adversary and affect both infrastructure and mobile ad hoc netw...

In this paper we propose an extension of the IEEE 802.11 DCF protocol [5] called PUMA (Priority Unavoidable Multiple Access). PUMA can easy be implemented in wireless network cards instead of IEEE 802.11 DCF. It has been shown through simulation that PUMA is fair, efficient, stable and allows for provision of time-bounded services. Moreover, its performance is unaffected by hidden stations. The...

Using a newly developed near-infrared (NIR) dye that fluoresces at two different wavelengths (dichromic fluorescence, DCF), we discovered a new fluorescent substrate for Akt, also known as protein kinase B, and a method to quantitatively report this enzyme's activity in real time. Upon insulin activation of cellular Akt, the enzyme multi-phosphorylated a single serine residue of a diserine DCF ...

The IEEE DCF 802.11 is currently used as WLAN standard. The standard specifies the contention-based MAC mechanism, Distributed Coordination Function (DCF), which allows to share the wireless channel. In the DCF each node picks a random contention slot from the uniform distribution over the [lower bound, upper bound] interval, where the lower bound always equals 0 and the upper bound equals an i...

We introduce the notion, issues, and challenges of dynamic coalition formation (DCF) among agents in open, heterogeneous and world widely distributed environments. Results achieved in the traditional field of static coalition formation are briefly discussed, as well as the desired results in the new research field of DCF. We propose a simulation-based DCF scheme, called DCF-S, to be applied to ...

We present a microstructure-based dual-core dispersion-compensating fiber (DCF) design for dispersion compensation in long-haul optical communication links. The design has been conceptualized by combining the all-solid dual-core DCF and dispersion-compensating photonic crystal fiber. The fiber design has been analyzed numerically by using a full vectorial finite difference time domain method. W...

In this work, various dispersion compensation methods are designed and evaluated to search for a cost-effective technique with remarkable dispersion compensation and a good pulse shape. The techniques consist of different chirp functions applied to a tanh fiber Bragg grating (FBG), a dispersion compensation fiber (DCF), and a DCF merged with an optimized linearly chirped tanh FBG (joint techniq...

Networking solutions, particularly wireless local area networks have revolutionized the technological advancement. Wireless Local Area Networks (WLANs) have gained a lot of popularity as they provide location-independent network access between computing devices. There are a number of access methods used in Wireless Networks among which DCF and PCF are the fundamental access methods. This paper ...

IEEE has standardized 802.11 protocol for Wireless Local Area Networks.The 802.11 MAC standard specifies two access mechanisms, the Distributed Coordination Function (DCF) and Point Coordination Function (PCF). DCF is considered as the basic MAC mechanism, based on the carrier sensing multiple access with collision avoidance (CSMA-CA) protocol, which is introduced to avoid the collision.The mai...