3,153 research outputs found
X.509 certificate error testing
X.509 Certificates are used by a wide range of technologies to verify identities, while the SSL protocol is used to provide a secure encrypted tunnel through which data can be sent over a public network. Combined both of these technologies provides the basis of the public key infrastructure (PKI). While the concept of PKI is a good idea, the different implementation of the technologies in different operating system and clients often lead to weaknesses. This paper proposes a methodology to automate the testing of SSL clients by generating both bogus and malformed certificates in order to evaluate the client’s response and identify potential threats to network infrastructures
Element-based Lattice Reduction aided K-Best detector for large-scale MIMO systems
Recently, large-scale Multiple-Input Multiple-Output (MIMO) systems have caught great attention for increasing the system throughput as well as improving the system performance. The main challenge in the design of these MIMO systems is the detection techniques used at the receiver. Lattice Reduction (LR) techniques have shown good potential in MIMO decoding due to their good performance and low complexity compared to Maximum Likelihood (ML) detector. The Lenstra, Lanstra, and Lovasz (LLL) LR algorithm has been employed for decoding while combined with linear detectors such as ZF as well as with K-Best detection. However, the LLL-aided detectors have shown limited performance, when increasing the number of antennas at the transmitter and receiver. Therefore, in this paper we propose to use the so-called Element-based Lattice Reduction (ELR) combined with K-Best detector for the sake of attaining a better BER performance and lower complexity than the LLL-aided detection. Explicitly, the ELR-aided detectors are capable of attaining a 2 dB performance improvement at BER of 10-5 compared to the LLL-aided detectors when considering a MIMO system with 200 transmit and receive antennas. Furthermore, for the same MIMO configuration, the ELR basis update requires nearly an order of magnitude reduction in the number of arithmetic operations compared to the LLL algorithm
Mehrwertorientierte Gestaltung mobiler Dienste im Fahrzeug : eine empirische Untersuchung von Nutzeranforderungen
Stagnierende Märkte und veränderte Kundenanforderungen eröffnen in der Automobilindustrie die Suche nach neuen, Erfolg versprechenden Geschäftsmodellen.
Automobilhersteller entdecken dabei zune
hmend das Potenzial des Mobile Business,
sehen sich bei der Erweiterung ihres ur
sprünglichen Kerngeschäftes durch die
Integration von mobilen Diensten in das
Fahrzeug jedoch gleichzeitig mit neuen
Herausforderungen konfrontiert. Um in den Augen der Nachfrager einen erkennbaren
Mehrwert zu stiften und somit die nutzerseitige Akzeptanz von mobilen Diensten im Fahrzeug zu sichern, müssen sich die Anbieter verstärkt an den Bedürfnissen ihrer Kunden orientieren.
Ausgangspunkt für die vorliegende Arbeit, der
en zentrales Ziel die Identifizierung und
Analyse nutzenstiftender Elemente von mobilen Diensten ist, sind die bisher
geringen Forschungsaktivitäten im Hinblick auf eine kundenorientierte Gestaltung
von mobilen Anwendungen im Fahrzeug. Eine Expertenbefragung soll zunächst
Aufschluss über die zentralen Eigenschaft
en des Leistungsbündels „mobile Dienste“
geben. Anschließend erfolgt auf Grundlage einer internetbasierten Konsumentenbefragung eine Analyse der Präferenzstrukturen von potenziellen Nutzern mobiler Dienste im Rahmen einer Adaptiven Conjoint-Analyse. Im letzten Untersuchungsschritt werden mittels einer Clusteranalyse homogene Käufergruppen
identifiziert und segmentspezifische Gestaltungsempfehlungen abgeleitet
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Si photocathode with Ag-supported dendritic Cu catalyst for CO2 reduction
Si photocathodes integrated with Ag-supported dendritic Cu catalysts are used to perform light-driven reduction of CO2 to C2 and C3 products in aqueous solution. A back illumination geometry with an n-type Si absorber was used to permit the use of absorbing metallic catalysts. Selective carrier collection was accomplished by a p+ implantation on the illumination side and an n+ implantation followed by atomic layer deposition of TiO2 on the electrolyte site. The Ag-supported dendritic Cu CO2 reduction catalyst was formed by evaporation of Ag followed by high-rate electrodeposition of Cu to form a high surface area structure. Under simulated 1 sun illumination in 0.1 M CsHCO3 saturated with CO2, the photovoltage generated by the Si (∼600 mV) enables C2 and C3 products to be produced at -0.4 vs. RHE. Texturing of both sides of the Si increases the light-limited current density, due to reduced reflection on the illumination side, and also deceases the onset potential. Under simulated diurnal illumination conditions photocathodes maintain over 60% faradaic efficiency to hydrocarbon and oxygenate products (mainly ethylene, ethanol, propanol) for several days. After 10 days of testing, contamination from the counter electrode is observed, which causes an increase in hydrogen production. This effect is mitigated by a regeneration procedure which restores the original catalyst selectivity. A tandem, self-powered CO2 reduction device was formed by coupling a Si photocathode with two series-connected semitransparent CH3NH3PbI3 perovskite solar cells, achieving an efficiency for the conversion of sunlight to hydrocarbons and oxygenates of 1.5% (3.5% for all products)
First Observations on the Mushroom in Mountain Area of Iraqi Kurdistan Region
Based on the collections made for mushroom between 1996-2010 in mountain areas in Sulaimani and Erbil Governorate especially in Soran, Joman, Sedakan districts Qandil and Zalm areas upto more than 3000 m.a.s.l. A total of 34 species in 23 genera, 17 families and 7 orders belong to woody and fleshy species were identified at the first time in Iraq
Multidisciplinary treatment for chronic pain: a systematic review of interventions and outcomes
Objectives. To provide an overview of the effectiveness of multidisciplinary treatments of chronic pain and investigate about their differential effects on outcome in various pain conditions and of different multidisciplinary treatments, settings or durations. Methods. In this article, the authors performed a systematic review of all currently available randomized controlled trials (RCTs) fulfilling the inclusion criteria, by using a recently developed rating system aimed to assess the strength of evidence with regard to the methodological quality of the trials. Results. Compared with other non-disciplinary treatments, moderate evidence of higher effectiveness for multidisciplinary interventions was shown. In contrast to no treatment or standard medical treatment, strong evidence was detected in favour of multidisciplinary treatments. The evidence that comprehensive inpatient programmes were more beneficial that outpatient programmes was moderate. Fibromyalgia and chronic back pain patients tended to profit more substantially than patients with diverse origins or chronic pain diagnoses. No evidence was found that treatment variables, such as duration or programme components, were influential for the success of the intervention. Conclusion. A standard of multidisciplinary programmes should be internationally established to guarantee generally good outcomes in the treatment of chronic pain. Our results highlight the lack of quality of design, execution or reporting of many of the RCTs included in this article. Future studies should more specifically focus on differential effects of treatment components and patient variables, allowing the identification of subgroups, which most probably would profit from multidisciplinary pain programme
Stacked optical antennas for plasmon propagation in a 5 nm-confined cavity
The sub-wavelength concentration and propagation of electromagnetic energy are two complementary aspects of plasmonics that are not necessarily co-present in a single nanosystem. Here we exploit the strong nanofocusing properties of stacked optical antennas in order to highly concentrate the electromagnetic energy into a 5 nm metal-insulator-metal (MIM) cavity and convert free radiation into guided modes. The proposed nano-architecture combines the concentration properties of optical nanoantennas with the propagation capability of MIM systems, paving the way to highly miniaturized on-chip plasmonic waveguiding
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