Krzysztof Cichon

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In cognitive radio, the secondary users are able to sense the spectral environment and use this information to opportunistically access the licensed spectrum in the absence of the primary users. In this paper, we present an experimental study that evaluates the performance of two different spectrum sensing techniques to detect primary user signals in real(More)
The dynamic spectrum access is a concept opposite to static frequency spectrum assignment and one of the key elements of cognitive radio (CR). It allows secondary users to access unused licensed frequency bands. In order to detect the presence of primary users, one of the fundamental tasks that a CR equipment has to perform is spectrum sensing process. In(More)
BACKGROUND Laparoscopic adjustable gastric banding (LAGB) is the third most popular bariatric procedure worldwide. Various authors present ambivalent long-term follow up results. METHODS We revised records of the patients who underwent LAGB between 2003 and 2006 along with history of additional check-ins. Patients with outdated details were tracked with(More)
INTRODUCTION Sleeve gastrectomy (LSG) is one of the most popular bariatric procedures. We present our long-term results regarding weight loss, comorbidities, and gastric reflux disease. MATERIAL AND METHODS We identified patients who underwent LSG in our institution between 2006 and 2009. We revised the data, and the patients with outdated contact details(More)
In this work, the energy consumption in the cooperative spectrum sensing is analysed. The analysis also covers the detection quality assessment and the definition of the energy efficiency (EE) metric. It is shown how cooperation among the sensing nodes affects the EE and how relaying of sensing information and node selection influences the detection(More)
In this paper we investigate two statistical estimators for the number of nodes in the Chord peer-to-peer system and one estimator for the number of information items stored in the system. The first estimator of the number of nodes is based on the Maximum Likelihood Estimation (MLE) technology and the second is based on the Methods of Moments (MM). We(More)
Cooperative spectrum sensing has been proposed as a solution to increase the sensing function accuracy in cognitive radio networks, but the research has, so far, mainly focused on static scenarios, all but neglecting the impact of mobility on spectrum sensing. In this work a novel cooperative spectrum sensing scheme for mobile cognitive networks, based on a(More)
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