Search results for " Cell"

Anomaly Detection Algorithms for the Sleeping Cell Detection in LTE Networks

2015

The Sleeping Cell problem is a particular type of cell degradation in Long-Term Evolution (LTE) networks. In practice such cell outage leads to the lack of network service and sometimes it can be revealed only after multiple user complains by an operator. In this study a cell becomes sleeping because of a Random Access Channel (RACH) failure, which may happen due to software or hardware problems. For the detection of malfunctioning cells, we introduce a data mining based framework. In its core is the analysis of event sequences reported by a User Equipment (UE) to a serving Base Station (BS). The crucial element of the developed framework is an anomaly detection algorithm. We compare perfor…

An efficient cluster-based outdoor user positioning using LTE and WLAN signal strengths

2015

In this paper we propose a novel cluster-based RF fingerprinting method for outdoor user-equipment (UE) positioning using both LTE and WLAN signals. It uses a simple cost effective agglomerative hierarchical clustering with Davies-Bouldin criterion to select the optimal cluster number. The positioning method does not require training signature formation prior to UE position estimation phase. It is capable of reducing the search space for clustering operation by using LTE cell-ID searching criteria. This enables the method to estimate UE positioning in short time with less computational expense. To validate the cluster-based positioning real-time field measurements were collected using readi…

Context-aware data caching for 5G heterogeneous small cells networks

2016

In this work, we investigate the problem of context-aware data caching in the heterogeneous small cell networks (HSCNs) to provide satisfactory to the end-users in reducing the service latency. In particular, we explore the storage capability of base stations (BSs) in HSCNs and propose a data caching model consists of edge caching elements (CAEs), small cell base stations (SBSs), and macro cell BS (MBS). Then, we concentrate on how to efficiently match the data contents to the different cache entities in order to minimize the overall system service latency. We model it as a distributed college admission (CA) stable matching problem and tackle this issue by utilizing contextual information t…

Data mining framework for random access failure detection in LTE networks

2014

Sleeping cell problem is a particular type of cell degradation. There are various software and hardware reasons that might cause such kind of cell outage. In this study a cell becomes sleeping because of Random Access Channel (RACH) failure. This kind of network problem can appear due to misconfiguration, excessive load or software/firmware problem at the Base Station (BS). In practice such failure might cause network performance degradation, which is hardly traceable by an operator. In this paper we present a data mining based framework for the detection of problematic cells. In its core is the analysis of event sequences reported by a User Equipment (UE) to a serving BS. The choice of N i…

SERS detection of cell surface and intracellular components of microorganisms using nano-aggregated Ag substrate

2016

Abstract The intracellular and cell surface composition and structural features of gram-positive and gram-negative bacteria were identified using near-infrared surface-enhanced Raman scattering (SERS). The structural differences of components that reside in the cell envelope are manifested by their SERS spectra, e.g. gram-negative vs. gram-positive. Silver particles were used as a SERS substrate by exploiting the existence of strong local electromagnetic fields (hot spots) within nanoscale aggregates of the particles. The aggregation of silver nanoparticles was induced by magnesium ions. These hot spots reduce the screening length of the double layer. The obtained SERS spectra showed excell…

Assessing travel time-based accessibility to outdoor ice skating fields for children in Helsinki during the COVID-19 pandemic

2022

This paper was written within the research project called “Equality in suburban physical activity environments, YLLI” (in Finnish: Yhdenvertainen liikunnallinen lähiö, YLLI) funded by the Suburban Programme 2020–2022 (in Finnish: Lähiöohjelma 2020–2022, decision number VN/10837/2020). Informal sport is central to Finnish children’s leisure and physical activity time. This paper aims to build a better understanding of the travel time-based accessibility to informal sports facilities, specifically to ice skating fields, for children and adolescents (aged 7–19) in the city of Helsinki. We focused on the winter of 2020–2021 because COVID-19 restrictions on indoor activities resulted in ice skat…

Doppler ultrasound and giant cell arteritis

2010

Ana Marina Suelves1, Enrique España-Gregori1,2, Jose Tembl3, Stephanie Rohrweck1, Jose Maria Millán4, Manuel Díaz-Llopis1,4,51Service of Ophthalmology, La Fe University Hospital, Valencia, Spain; 2Department of Optics, University of Valencia, Valencia, Spain; 3Service of Neurology, La Fe University Hospital, Valencia, Spain; 4CIBERER, Ciber de Enfermedades Raras, Valencia, Spain; 5Faculty of Medicine, University of Valencia, Valencia, SpainObjective: To evaluate the utility of ultrasound in aiding the diagnosis of giant cell arteritis (GCA), in monitoring the response to corticotherapy, and in detecting early relapses.Methods: A pilot study, prospective, inc…

EFFETTO DI TERRENI CONDIZIONATI DA NEURONI ED ASTROCITI SULLE PROPRIETÀ BARRIERA DI CELLULE DEI CAPILLARI CEREBRALI.

2004

Vers des indicateurs locaux de performance énergétique : les étiquettes énergétiques territoriales

2013

24; Le constat d'un changement climatique planétaire est à l'origine d'un objectif très concret de réduction des émissions de gaz à effets de serre, lui-même nécessairement corrélé à une réduction de la consommation énergétique globale. A l'échelle locale, cette perspective se traduit par la définition d'objectifs concrets en matière de maîtrise et d'amélioration de l'efficacité énergétique, et peut passer par la définition d'indicateurs qui guideront l'action des décideurs. Dans ce contexte, à partir de l'exemple de l'agglomération de Besançon, la recherche présentée ici vise à définir un indicateur énergétique utile aux aménageurs : il s'agit de mesurer comment " se situent énergétiquemen…

I TERATOMI DEL TESTICOLO: Considerazioni da una Casistica Nazionale Multicentrica sui Tumori Primitivi del Testicolo in Età Pediatrica

1991

The authors analyze the results of a national multicentric series of primary testis tumors and present cases of testicular teratomas. Incidence, clinical characteristics and the therapeutic procedure followed are highlighted.