Norwegian Defence Research Establishment Research Articles

Angular dependence of acoustic scattering statistics for rocky outcrops

The use of automated detection algorithms in undersea remote sensing and target detection allows for decreased timelines and risk to human assets. However, understanding the performance of these systems requires a thorough understanding of the physical processes that affect the acoustic scattering statistics of the sonar image. Many studies have reported on the scattering statistics of the seafloor generally, and recent work has quantified the dependence of scintillation index on range for sandy seafloors. To date, no studies have examined the angular dependence of acoustic scattering statistics for rocky bottoms, which have more complex spatial texture. This paper analyzes synthetic aperture sonar (SAS) images of rocky outcrops imaged near Bergen Norway to quantify the grazing angle dependency of scattering statistics for rocky seafloors. Outcrops are categorized by texture and analyzed using scintillation index and relative scattering strength with respect to both true grazing angle and a flat seafloor assumption. Comparisons between results utilizing calibrated (beampattern removed) and non-calibrated images will be presented to display the complexity of the grazing angle dependence of scattering statistics for rocky seafloors. SAS imagery provided by the Norwegian Defence Research Establishment. [Funding provided by the Office of Naval Research]

Scattering statistics of nonstationary seafloors: Mixture models and choosing the number of components

Modern high resolution synthetic aperture sonars are capable of resolving the structure of patchy seafloors, defined as seafloors having non-stationarygeoacoustic and roughness properties. Within each patch, it is often possible to model the amplitude statistics using commonly used physics based statistical models, such as the K-distribution. However, it is impossible to use on a large scale because either the parameters change from patch to patchor the imaging sonar alters the scattering statistics at different ranges. Here, we propose a method to segment different patches in a sonar image using a mixture of physicallymotivated statistical models. We detail how the number of components can be chosen using Bayesian model selection techniques, such as the deviance information criterion. The tradeoff between model accuracy and robustness is explored using a dataset provided by the Norwegian Defence Research Establishment.

Introducing the Jihadi Plots in Europe Dataset (JPED)

The article introduces a new dataset on terrorist attack activity by jihadis in Western Europe. The dataset was built over nearly two decades at the Norwegian Defence Research Establishment. It records not only attacks that were launched, but also plots that were foiled by counterterrorism. The rationale behind the dataset is that analyses based on launched attacks may misrepresent the scale and nature of terrorism. The article shows that if we were to measure the jihadi threat to Europe by attacks only we would miss out on 58.2% of the total attack activity. We also show that while attack data signify a trend towards small attacks by individuals, these data hide the fact that terror networks persist in plotting big attacks that get foiled. We discuss how analyses based on attacks only may distort comparative analyses of different types of terrorists across countries, as well as causal analyses of terrorism drivers. By including foiled plots we gain a fuller picture of terrorism. The Jihadi Plots in Europe Dataset allows the gauging of different aspects of the threat from Al-Qaida and Islamic State in Europe. The dataset documents when and where terror plots occur, whether or not they result in attacks, and different types of information about perpetrators and how they operate. The Dataset offers a reliable overview of jihadi terrorism in Europe for research and policy.

The Use and Misuse of Wargames

Since 2015, there has been a resurgence in the use of wargaming in NATO states. But countries with smaller wargaming communities have not seen a corresponding revitalization of the technique. If the interest is there, the capability often lacks. The paper argues that a critical first step in stimulating the role of wargaming in these countries is ensuring that local practitioners know of each other, so they can exchange experiences on gaming results and practices; further, they need an understanding of what wargaming might (and might not) be, and the steps necessary to make the technique work in practice. The paper offers experiences from wargames conducted by analysts and researchers at the Norwegian Defence Research Establishment (FFI), for the most part games on the strategic and operational level. The experiences are structured as eight broad lessons on “dos and don’ts” to consider when planning and running wargames, based on recurring practical issues in past games. While the lessons are drawn from experiences within a small wargaming community, many of the issues discussed are universal for wargaming at large.

Simulation-Supported Wargaming for Assessing Force Structures

Wargaming is a key activity for gaining deeper insight into the strengths and weaknesses of future force structures in the course of their development and assessment. For more than a decade, the Norwegian Defence Research Establishment (Forsvarets forskningsinstitutt – FFI) has supported the Norwegian Army in conducting wargames for capability planning, with varying degrees of computer-based support. Throughout this period, these have evolved from what can be described as computer-assisted wargames to more realistic simulation-supported wargames. Moreover, to get a closer understanding of the deterrent effect of the force structures, which may not be observable during the actual gameplay, our emphasis has also shifted towards replicating the planning process more properly – and especially towards monitoring the planning process of the opposing force. For example, it has been important to examine the extent to which specific structure elements discourage the opposing force from taking certain actions. In this article, we describe our evolved methodology for simulation-supported wargaming, which includes a preparation phase; an execution phase, including a joint operational planning process; and an analysis phase. Furthermore, we discuss what type of data and results we are able to extract from the wargaming sessions, and present a set of what we have found to be best practices for how to conduct successful simulation-supported wargames.

Wargaming Dos and Don’ts – Eight Lessons for Planning and Conducting Wargames

Since 2015, there has been a resurgence in the use of wargaming in NATO states. But countries with smaller wargaming communities have not seen a corresponding revitalization of the technique. If the interest is there, the capability often lacks. The paper argues that a critical first step in stimulating the role of wargaming in these countries is ensuring that local practitioners know of each other, so they can exchange experiences on gaming results and practices; further, they need an understanding of what wargaming might (and might not) be, and the steps necessary to make the technique work in practice. The paper offers experiences from wargames conducted by analysts and researchers at the Norwegian Defence Research Establishment (FFI), for the most part games on the strategic and operational level. The experiences are structured as eight broad lessons on “dos and don’ts” to consider when planning and running wargames, based on recurring practical issues in past games. While the lessons are drawn from experiences within a small wargaming community, many of the issues discussed are universal for wargaming at large.

Modeling the effects of internal waves on synthetic aperture sonar resolution

Synthetic aperture sonar (SAS) beamforming is performed under the assumption of a constant sound speed within the water column or by utilizing a measured sound speed profile. Water column features, such as internal waves or internal wave boluses that cause a sound speed structure different than that assumed, can break the constant sound speed assumption resulting in image defocusing and loss of resolution. The resultant loss of resolution can be quantified using the point spread function (PSF). An ellipse fitting technique was applied to SAS images collected by the Norwegian Defence Research Establishment (FFI) using the HISAS system. In conjunction with the analysis conducted on real data, a ray tracing method was applied to model the broadening effects on the PSF for sound speed differences caused by internal wave boluses. A wavenumber beamforming algorithm was also applied to artificial echo data, in which sound speed errors were introduced. It is hoped that the two models can be used in conjunction with SAS data to determine the sound speed within an internal wave feature from the observed loss in resolution.

Russiske kjernefysiske styrker

Dr. Kristin Ven Bruusgaard reviews the report Russian Nuclear Forces written by Steinar Høibråten and Halvor Kippe at the Norwegian Defence Research Establishment.

Rusland som militær stormagt

Russia as a Military Power, edited by Niels Bo Poulsen and Jørgen Staun (Djøf Forlag 2021) is reviewed by Tor Bukkvoll, of the Norwegian Defence Research Establishment (FFI).

Worried in Sweden: the effects of terrorism abroad and news media at home on terror-related worry

We investigate whether terrorist activity abroad affects worry regarding terrorism in Sweden, and the possible mediating effect of news media. Terrorism uses violence to obtain political or social objectives: in addition to the impact on the immediate victims, terrorism affects a much wider audience emotionally by spreading fear and insecurity. Previous research shows that terrorist attacks in a country cause worry for the people in that country; however, little is known about the relationship between public worry and terrorist attacks abroad. This study draws from the Global Terrorism Database (GTD), the Norwegian Defence Research Establishment (FFI), the Swedish press archive Mediearkivet, and the Swedish National Annual Survey (SOM), producing a theoretical model using Generalized Structural Equation Modelling (GSEM). The results show that public worry about terrorism co-varies with the frequency of terrorist activity occurring in the wider geo-cultural region, even if outside of the country of residence. It also shows that public worry is affected not only by single, impactful attacks – so-called ‘one-off’ attacks – but also by an increase in the number of total (even if less individually impactful) attacks in the region. Notably, media coverage ameliorates the impact of terrorism on public worry to some degree. For policy makers these results are particularly important since they show that even in countries free of terrorist events, public fear needs to be managed.

Russian Military Capability in a Ten-Year Perspective – 2019

Abstract: Russian Military Capability in a Ten-Year Perspective – 2019Una Hakvåg (Norwegian Defence Research Establishment (FFI)) reviews Russian Military Capability in a Ten-Year Perspective – 2019, an analysis of Russia’s Armed Forces and their fighting power, edited by Fredrik Westerlund & Susanne Oxenstierna.

Fuel cell systems for long-endurance autonomous underwater vehicles – challenges and benefits

Autonomous underwater vehicles (AUVs) are programmable, robotic vehicles that can drift, drive, or glide through the ocean without real-time control by human operators. AUVs that also can follow a planned trajectory with a chosen depth profile are used for geophysical surveys, subsea pipeline inspection, marine archaeology, and more. Most AUVs are followed by a mother ship that adds significantly to the cost of an AUV mission. One pathway to reduce this need is to develop long-endurance AUVs by improving navigation, autonomy and energy storage. Long-endurance AUVs can open up for more challenging mission types than what is possible today. Fuel cell systems are a key technology for increasing the endurance of AUVs beyond the capability of batteries. However, several challenges exist for underwater operation of fuel cell systems. These are related to storage or generation of hydrogen and oxygen, buoyancy and trim, and the demanding environment of the ambient seawater. Protecting the fuel cell inside a sealed container brings along more challenges related to condensation, cooling and accumulation of inert gases or reactants. This paper elaborates on these technical challenges and describes the solutions that the Norwegian Defence Research Establishment (FFI) has chosen in its development of a fuel cell system for long-endurance AUVs. The reported solutions enabled a 24 h demonstration of FFI's fuel cell system under water. The remaining work towards a prototype sea trial is outlined.

NASA's alphasat propagation terminals: Milan, Italy, and Edinburgh, Scotland

SummarySince May of 2014, NASA's Glenn Research Center has operated measurement campaigns for the Alphasat Aldo Paraboni Propagation Experiment alongside the European community of propagation experimenters. Presently, three NASA stations have been deployed to distinct climatological regions across Europe. NASA's participation in the campaign began in 2014 through a collaborative effort with the Politecnico di Milano (POLIMI) to jointly operate a 20/40 GHz ground terminal at the POLIMI campus in Milan, Italy. Subsequently, a single‐channel 40 GHz terminal was deployed to Edinburgh, Scotland in March 2016 in collaboration with Heriot‐Watt University (HWU). A third terminal was deployed to NASA's Madrid Deep Space Communications Complex (MDSCC) in March 2017 with NASA'S Jet Propulsion Laboratory (JPL), also observing the 40 GHz beacon. In addition, a fourth station is planned for deployment to Andøya, Norway by early 2019 in collaboration with the Norwegian Defence Research Establishment (FFI). This paper will detail the design and results of the two most established terminals, Milan and Edinburgh, which together comprise 11 station years of propagation measurements.

A Slice of Norways Computing History

Yngvar Lundh was instrumental in the development of some of Norways earliest digital computers, having started his investigation of digital electronics in the 1950s. He continued his involvement with digital computers and digital communications for the next 40 years. The pioneering digital work at Norwegian Defence Research Establishment is the focus of Lundhs anecdote, particularly the hardware development activities and then early involvement with internetworking.

Quantifying the effect of random roughness on synthetic aperture sonar image statistics

A perturbation-theory-based model has been developed to predict the effect of random seafloor roughness on synthetic aperture sonar (SAS) image statistics. The continuous variation in scattering strength produced by a random slope field is treated as an intensity scaling on image speckle produced by the SAS imaging process. Changes in image statistics caused by roughness are quantified in terms of the scintillation index (SI). Factors influencing the SI include slope variance, geo-acoustic properties of the seafloor, the probability density function describing the speckle and the signal-to-noise ratio. Example model-data comparisons will be shown for SAS images taken off the coast of Tellaro, Italy, by the NATO Undersea Research Centre, La Spezia, Italy (now the NATO Centre for Maritime Research and Experimentation) using the 300 kHz MUSCLE SAS system, and for data collected with the Norwegian Defence Research Establishment’s 100 kHz HISAS system off the coast of northwest coast of Elba Island, Italy, in ...

A Slice of Norway’s Computing History

Yngvar Lundh was instrumental in the development of some of Norway’s earliest digital computers, having started his investigation of digital electronics in the 1950s. He continued his involvement with digital computers and digital communications for the next 40 years. A 10 April 2017 article about Lundh in the Norwegian online information and telecommunications newspaper digi.no quotes another pioneer of Norwegian computing, saying, “Yngvar Lundh is the most important person in Norwegian IT ever.” The pioneering digital work at the Norwegian Defence Research Establishment is the focus of Lundh’s report here, particularly the hardware development activities and early involvement with internetworking.

Events and Sightings

Events and Sightings David Walden (bio) and Dag Spicer (bio) Fifty-Year Anniversaries in Norwegian Computing History Two fifty-year anniversaries in computing history were celebrated in Oslo in September 2017: the fifty-year anniversary of the creation of the Simula programming language, and the fifty-year anniversary of the founding of the Norsk Data computer company. Simula The Simula 67 programming language, first formally defined in 1967, was a step in a series of developments by Ole-Johan Dahl and Kristen Nygaard that began in the early 1960s.1 Dahl and Nygaard were given the 2001 IEEE John von Neumann Medal and the ACM 2001 A.M. Turing Award for their creation of Simula. A fifty-year anniversary celebration for Simula took place (in the “Simula Auditorium” in the “Ole-Johan Dahl Building”) at the University of Oslo on 27 September 2017. The celebration began with unveiling of a plaque from the IEEE History Committee’s Milestone program. The plaque reads: IEEE Milestone Object-oriented Programming, 1961–1967 Ole-Johan Dahl and Kristen Nygaard created the Simula programming languages in the 1960s at the Norwegian Computer Center, and in so doing introduced a new way of modeling and simulating complex tasks. Object-oriented programming is now dominant in systems development. It is an integral part of computer science curricula, as are languages built on object-oriented programming concepts, such as Smalltalk, C++, Java, and Python. September 2017 The nomination of this Milestone was from the IEEE Norway Section. The photo shows Section Vice-Chairman Kaveh Niayesh unveiling the plaque. The rest of the day consisted of presentations by several programming language researchers and developers: Oscar Nierstrasz (“Great Moments in the History of OOP”), Dave Thomas (“The Legacy of Simula 67”), and James Gosling (“Simula: A Personal Journey”), as well as a panel discussion chaired by Eric Jul (“Whither Programming Languages? Can We Still Celebrate Simula 50 Years from Now?”) with participation of the prior three speakers and Ole Lehrmann Madsen and Olaf Owe.2 Videos from the event are available.3 The previous afternoon, the Association of Simula Users (ASU) held a several-hour meeting at which there were six presentations and a wrap-up session. According to Boris Magnusson (ASU chairman 1982–83), the ASU has been in continuous existence since the early days of Simula 67, holding annual conferences and publishing a quarterly newsletter. However, in recent years the ASU activities “have slowly faded away, and the meeting in Oslo was intended as a last meeting and also a way to formally close down the Association.” Click for larger view View full resolution Photo 1. Photo credit: Harald Brombach/digi.no. Norsk Data On 16–17 September 2017, the fiftieth anniversary of the founding of Norsk Data was marked. In 1967 Lars Monrad-Krohn, Per Bjørge, and Rolf Skår left the Norwegian Defence Research Establishment (NDRE), where they had worked on the computer developments in “Siffergruppen” (the Digital Group), initiated and [End Page 93] led by Yngvar Lundh. They founded Norsk Data Elektronikk, where their first computer development was the Nord-1, building on work they had done in the Digital Group. Click for larger view View full resolution Photo 2. Veslemøy Østrem of Aftenposten interviewing Norsk Data founders Rolf Skår and Lars Monrad-Krohn. Photo credit: Ragnar Sturzel. The Nord-1was a minicomputer and competed well in Europe with minicomputers from the United States. With additional computers being developed over the years (arguably better hardware and software than some US competitors) and many high-profile or operation-critical installations, Norsk Data eventually became a high-flying company listed on the London as well as the NASDAQ stock exchanges, in addition to on the Norwegian exchange. With the personal computer revolution, Norsk Data went the way of almost all minicomputer manufacturers, eventually going out of business. For many of the eventual 4,500 employees of Norsk Data, their time with a company was one of the most exciting times of their professional careers, and the one-time employees of Norsk Data went on to populate a significant part of the developing Norwegian computing industry. The day of 18 September involved a five-hour...

From F-16 to F-35: Optimizing the Training of Pilots in the Royal Norwegian Air Force

The Norwegian Armed Forces will soon make the largest investment in its history. It plans to spend $8 billion to replace the Royal Norwegian Air Force’s existing fleet of F-16 aircraft with 52 new F-35 aircraft. The Norwegian Defence Research Establishment (FFI) has undertaken multiple analyses to support the Norwegian Defence Logistics Organisation (NDLO) with the transition planning. During the transition period, Norway must maintain adequate fighter capability. The rate at which it can train new pilots and convert F-16 pilots to fly the F-35 will influence the cost and length of the transition period and the Air Force’s operational-readiness status. Although finding the optimal training rate for pilots is a difficult planning problem, we achieved substantial success by using an integer linear program to generate optimal plans. By using this model, we were able to investigate multiple scenarios for pilot training. We determined the earliest year that the Air Force could reach a fully operational F-35 fighter capability, the optimal ratio of new to converted pilots, and the number of pilots that FFI should train each year during the transition phase. Our results enabled FFI to generate a training plan that resulted in large savings and operational advantages compared to the previous solution, which did not employ operations research techniques for planning.

24 Hour Test of the Fuel Cell System for an Autonomous Underwater Vehicle

The Norwegian Defence Research Establishment (FFI) has a long experience with power sources for autonomous underwater vehicles (AUVs). FFI has designed and built a power supply system based on a water-cooled and air-supplied PEM fuel cell stack from Ballard, run on air. Hydrogen is supplied from a pressure tank, while oxygen is produced by catalytic decomposition of industrial grade hydrogen peroxide. Excess hydrogen is catalytically combined with oxygen in the internal atmosphere of the pressure hull. The fuel cell system is fully automated and self-regulating according to the set current. A 24 hour continuous test of the system was conducted in a sealed pressure hull under water. The system showed stable and reliable performance throughout the test, with only a small and regenerative voltage decrease.

Quantifying the tracking capability of space-based AIS systems

The Norwegian Defence Research Establishment (FFI) has operated three Automatic Identification System (AIS) receivers in space. Two are on dedicated nano-satellites, AISSat-1 and AISSat-2. The third, the NORAIS Receiver, was installed on the International Space Station. A general method for calculating the upper bound on the tracking capability of a space-based AIS system has been developed and the results from the algorithm applied to AISSat-1 and the NORAIS Receiver individually. In addition, a constellation of AISSat-1 and AISSat-2 is presented. The tracking capability is defined as the probability of re-detecting ships as they move around the globe and is explained to represent and upper bound on a space-based AIS system performance. AISSat-1 and AISSat-2 operates on the nominal AIS1 and AIS2 channels, while the NORAIS Receiver data used are from operations on the dedicated space AIS channels, AIS3 and AIS4. The improved tracking capability of operations on the space AIS channels is presented.