Defence Forces Technical Research Center


Defence Forces Technical Research Center

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Fykse E.M.,Norwegian Defence Research Establishment FFI | Tjarnhage T.,Swedish Defence Research Agency | Humppi T.,Defence Forces Technical Research Center | Eggen V.S.,Norwegian Defence Research Establishment FFI | And 8 more authors.
Aerobiologia | Year: 2015

The aim of this study was to collect and identify airborne bacteria in Norway, Sweden and Finland and to compare three different technologies for identifying collected airborne bacterial isolates: the “gold standard” method 16S rDNA sequencing, MALDI-TOF MS using the MALDI Biotyper 2.0 and the MIDI Sherlock® Microbial Identification System (MIDI MIS system). Airborne bacteria were collected during three different periods from May to October 2009 using air sampling directly on agar plates. A total of 140 isolates were collected during three sampling campaigns, and 74 % (103) of these isolates were analyzed by all three methods. The dominant genera in Norway and Finland were the gram-positive bacteria Bacillus and Staphylococcus, whereas the gram-negative bacterium Acinetobacter was the dominant genus in Sweden. Using 16S rDNA sequencing, MALDI-TOF MS and MIDI MIS analysis, 83, 79 and 75 %, respectively, of the isolates were identified and assigned to order or higher taxonomic levels. In this study, the MALDI-TOF MS combining with the MALDI Biotyper 2.0 classification tool was demonstrated to be a fast and reliable alternative for identifying the airborne bacterial isolates. These studies have increased knowledge about the airborne bacterial background in outdoor air, which can be useful for evaluating and improving the operational performance of biological detectors in various environments. To our knowledge, this is the first time that 16S rDNA sequencing, MALDI-TOF MS and MIDI MIS analysis technologies have been compared for their efficiency in identifying airborne bacteria. © 2015, Springer Science+Business Media Dordrecht.

Masson O.,Institute for Radiological Protection and Nuclear Safety | Baeza A.,Laruex | Bieringer J.,Institute Atmospharische Radioaktivitat | Brudecki K.,Polish Academy of Sciences | And 75 more authors.
Environmental Science and Technology | Year: 2011

Radioactive emissions into the atmosphere from the damaged reactors of the Fukushima Dai-ichi nuclear power plant (NPP) started on March 12th, 2011. Among the various radionuclides released, iodine-131 ( 131I) and cesium isotopes ( 137Cs and 134Cs) were transported across the Pacific toward the North American continent and reached Europe despite dispersion and washout along the route of the contaminated air masses. In Europe, the first signs of the releases were detected 7 days later while the first peak of activity level was observed between March 28th and March 30th. Time variations over a 20-day period and spatial variations across more than 150 sampling locations in Europe made it possible to characterize the contaminated air masses. After the Chernobyl accident, only a few measurements of the gaseous 131I fraction were conducted compared to the number of measurements for the particulate fraction. Several studies had already pointed out the importance of the gaseous 131I and the large underestimation of the total 131I airborne activity level, and subsequent calculations of inhalation dose, if neglected. The measurements made across Europe following the releases from the Fukushima NPP reactors have provided a significant amount of new data on the ratio of the gaseous 131I fraction to total 131I, both on a spatial scale and its temporal variation. It can be pointed out that during the Fukushima event, the 134Cs to 137Cs ratio proved to be different from that observed after the Chernobyl accident. The data set provided in this paper is the most comprehensive survey of the main relevant airborne radionuclides from the Fukushima reactors, measured across Europe. A rough estimate of the total 131I inventory that has passed over Europe during this period was <1% of the released amount. According to the measurements, airborne activity levels remain of no concern for public health in Europe. © 2011 American Chemical Society.

Lappi E.,Defence Forces Technical Research Center | Pakkanen M.S.,Defence Forces Technical Research Center | Akesson B.,Defence Forces Technical Research Center
Proceedings - Winter Simulation Conference | Year: 2012

We develop a dynamic Markovian method of simulating a battle between two infantry units. Its key feature is that the probabilities of the outcomes of the battle can be computed efficiently, without the joint distribution of the strengths of the units or their transition matrix, making the method feasible even with larger unit strengths. We find the probabilities of the outcomes to be close to the ones obtained from a more elaborate, but computationally more costly, joint Markov-chain model of strengths. Additionally, using our method we are able to compute the conditional distributions of the strength of a unit, given that it has, respectively, won the battle or been defeated by the enemy. © 2012 IEEE.

Manninen A.,Center for Metrology and Accreditation | Kaariainen T.,Center for Metrology and Accreditation | Parviainen T.,Defence Forces Technical Research Center | Buchter S.,Lasersec Systems Ltd. | And 3 more authors.
Optics Express | Year: 2014

A hyperspectral remote sensing instrument employing a novel near-infrared supercontinuum light source has been developed for active illumination and identification of targets. The supercontinuum is generated in a standard normal dispersion multi-mode fiber and has 16 W total optical output power covering 1000 nm to 2300 nm spectral range. A commercial 256-channel infrared spectrometer was used for broadband infrared detection. The feasibility of the presented hyperspectral measurement approach was investigated both indoors and in the field. Reflection spectra from several diffusive targets were successfully measured and a measurement range of 1.5 km was demonstrated. © 2014 Optical Society of America.

Bhuiyan M.Z.H.,Finnish Geodetic Institute | Kuusniemi H.,Finnish Geodetic Institute | Airos E.,Defence Forces Technical Research Center
Radioengineering | Year: 2014

A GNSS-based navigation system relies on externally received information via a space-based Radio Frequency (RF) link. This poses susceptibility to RF Interference (RFI) and may initiate failure states ranging from degraded navigation accuracy to a complete signal loss condition. To guarantee the integrity of the received GNSS signal, the receiver should either be able to function in the presence of RFI without generating misleading information (i.e., offering a navigation solution within an accuracy limit), or the receiver must detect RFI so that some other means could be used as a countermeasure in order to ensure robust and accurate navigation. Therefore, it is of utmost importance to identify an interference occurrence and not to confuse it with other signal conditions, for example, indoor or deep urban canyon, both of which have somewhat similar impact on the navigation performance. Hence, in this paper, the objective is to investigate the effect of interference on different GNSS receiver observables in two different environments: i. an interference scenario with an inexpensive car jammer, and ii. an outdoorindoor scenario without any intentional interference. The investigated observables include the Automatic Gain Control (AGC) measurements, the digitized IF (Intermediate Frequency) signal levels, the Delay Locked Loop and the Phase Locked Loop discriminator variances, and the Carrier-to-noise density ratio (C/N0) measurements. The behavioral pattern of these receiver observables is perceived in these two different scenarios in order to comprehend which of those observables would be able to separate an interference situation from an indoor scenario, since in both the cases, the resulting positioning accuracy and/or availability are affected somewhat similarly. A new Running Digital Sum (RDS) -based interference detection method is also proposed herein that can be used as an alternate to AGC-based interference detection. It is shown in this paper that it is not at all wise to consider certain receiver observables for interference detection (i.e., C/N0); rather it is beneficial to utilize certain specific observables, such as the RDS of raw digitized signal levels or the AGC-based observables that can uniquely identify a critical malicious interference occurrence.

Ruoskanen J.,Defence Forces Technical Research Center | Ruokokoski T.,Harp Technologies Ltd. | Lahtinen J.,Harp Technologies Ltd.
IET Conference Publications | Year: 2012

The examination of kurtosis statistics of a received signal is a well-known technique for detecting unwanted radio frequency interference (RFI) in passive remote sensing applications, which measure thermal noise [5]. The RFI removal is often carried out in post processing stage. In contrast to the mitigation of the RFI in remote sensing data, the kurtosis analysis can also be utilized to detect weak and noisy signals in the fields of electronic warfare and signal intelligence. The kurtosis algorithm can be incorporated into real time systems, thus increasing their probability of detection by several decibels. In this paper we will present the optimal performance of the kurtosis algorithm in terms of interception of pulsed radar waveforms.

Akesson B.M.,Defence Forces Technical Research Center | Lappi E.,Defence Forces Technical Research Center | Pettersson V.H.,Defence Forces Technical Research Center | Malmi E.,Defence Forces Technical Research Center | And 3 more authors.
Journal of Defense Modeling and Simulation | Year: 2013

Field experiments were used to evaluate three different indirect fire models: the cookie cutter and the Carleton damage functions and a simplified physical model for fragmenting ammunition. Data from three field tests, in which a total of 66 mortar bombs (120 mm high explosive) were fired in flat terrain, is used for validation. The results imply that no universal parameters, that would fit the results, can be found for the damage function models while the physical model predicted the field test results consistently without parameter fitting. © 2013 The Society for Modeling.

Kylmala J.,Defence Forces Technical Research Center | Salminen V.-J.,Defence Forces Technical Research Center | Tuohimaa A.,Defence Forces Technical Research Center | Lensu T.,Army Materiel Command
Proceedings International Radar Symposium | Year: 2013

Non-co-operative target recognition can be a valuable capability in a military search radar in various situations /1/. An unidentified observed target can be any of many different things: A civilian light aircraft, a flock of birds or a swarm of insects, a drone, a commercial airliner, a military aircraft, a cruise missile etc. Air defense system controllers need to know what the target type is - long before it is decided how to react to it. In most cases ISAR (Inverse Synthetic Aperture Radar) is the only way to get a firm confirmation of the target type in a quick manner and from a long range /2/. © 2013 German Inst of Navigation.

Antonioni G.,University of Bologna | Burkhart S.,Directorate General of Armaments | Burman J.,Swedish Defence Research Agency | Dejoan A.,CIEMAT | And 8 more authors.
Atmospheric Environment | Year: 2012

Chemical plants, refineries, transportation of hazardous materials are some of the most attractive facilities for external attacks aimed at the release of toxic substances. Dispersion of these substances into the atmosphere forms a concentration distribution of airborne pollutants with severe consequences for exposed individuals. For emergency preparedness and management, the availability of assessed/validated dispersion models, which can be able to predict concentration distribution and thus dangerous zones for exposed individuals, is of primary importance. Air quality models, integral models and analytical models predict the transport and the turbulent dispersion of gases or aerosols after their release without taking into account in detail the presence of obstacles. Obstacles can modify the velocity field and in turn the concentration field. The Computational Fluid Dynamics (CFD) models on the other hand are able to describe such phenomena, but they need to be correctly set up, tested and validated in order to obtain reliable results. Within the project Europa-ERG1 TA 113.034 "NBC Modelling and Simulation" several different approaches in CFD modelling of turbulent dispersion in closed, semi-confined and urban-like environment were adopted and compared with experimental data and with operational models. In this paper the results of a comparison between models describing the dispersion of a neutral gas in an idealized urban-like environment are presented and discussed. Experimental data available in the literature have been used as a benchmark for assessing statistical performance for each model. Selected experimental trials include some water channel tests, that were performed by Coanda at 1:205 scale, and one full-scale case that was tested in the fall of 2001 at the Dugway Proving Grounds in Utah, using an array of shipping containers. The paper also suggests the adoption of improved statistical parameters in order to better address differences between models, and to have a more straightforward method for comparing models suitable for emergency preparedness aims. © 2011 Elsevier Ltd.

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