Piggybacking on an Autonomous Hauler: Business Models Enabling a System-of-Systems Approach to Mapping an Underground Mine

With ever-increasing productivity targets in mining operations, there is a growing interest in mining automation. In future mines, remote-controlled and autonomous haulers will operate underground guided by LiDAR sensors. We envision reusing LiDAR measurements to maintain accurate mine maps that would contribute to both safety and productivity. Extrapolating from a pilot project on reliable wireless communication in Boliden's Kankberg mine, we propose establishing a system-of-systems (SoS) with LIDAR-equipped haulers and existing mapping solutions as constituent systems. SoS requirements engineering inevitably adds a political layer, as independent actors are stakeholders both on the system and SoS levels. We present four SoS scenarios representing different business models, discussing how development and operations could be distributed among Boliden and external stakeholders, e.g., the vehicle suppliers, the hauling company, and the developers of the mapping software. Based on eight key variation points, we compare the four scenarios from both technical and business perspectives. Finally, we validate our findings in a seminar with participants from the relevant stakeholders. We conclude that to determine which scenario is the most promising for Boliden, trade-offs regarding control, costs, risks, and innovation must be carefully evaluated.Comment: Preprint of industry track paper accepted for the 25th IEEE International Conference on Requirements Engineering (RE'17

Video Game Development in a Rush: A Survey of the Global Game Jam Participants

Video game development is a complex endeavor, often involving complex software, large organizations, and aggressive release deadlines. Several studies have reported that periods of "crunch time" are prevalent in the video game industry, but there are few studies on the effects of time pressure. We conducted a survey with participants of the Global Game Jam (GGJ), a 48-hour hackathon. Based on 198 responses, the results suggest that: (1) iterative brainstorming is the most popular method for conceptualizing initial requirements; (2) continuous integration, minimum viable product, scope management, version control, and stand-up meetings are frequently applied development practices; (3) regular communication, internal playtesting, and dynamic and proactive planning are the most common quality assurance activities; and (4) familiarity with agile development has a weak correlation with perception of success in GGJ. We conclude that GGJ teams rely on ad hoc approaches to development and face-to-face communication, and recommend some complementary practices with limited overhead. Furthermore, as our findings are similar to recommendations for software startups, we posit that game jams and the startup scene share contextual similarities. Finally, we discuss the drawbacks of systemic "crunch time" and argue that game jam organizers are in a good position to problematize the phenomenon.Comment: Accepted for publication in IEEE Transactions on Game

Multichannel Segmentation vs. Demographic Segmentation

The aim of this study is to generate a multichannel segmentation model for high involvement products and to compare it to the widely spread demographic segmentation. In addition, the study also aims to identify demographic and psychographic profiles to provide a rich descriptive picture of the new customer segments. The study combines the literature of the multichannel and segmentation fields. Moreover, it builds upon the knowledge of previous multichannel segmentation models, which exclusively focused on specific product categories and industries by investigating the effects of a high product involvement on consumers’ channel preferences and channel selections. To accomplish these aims, the study at hand utilizes a quantitative approach within the frame of a single case study that focuses on IKEA Sweden. The analysis reveals that the multichannel segmentation model entails a unique set of segments when looking at high involvement products. These segments are strongly directed towards offline channels as three out of four segments showed preferences for offline channels while only one segment showed a slight preference for online channels. Furthermore, two segments selected offline channels exclusively. The other two segments display a multichannel behavior as they selected both offline and online channels for purchasing high involvement products, yet these two segments selected offline channels more recently than online channels. Additionally, the multichannel segmentation model might be a more contemporary relevant segmentation model than the traditional demographic segmentation model. Even though these findings are only directly applicable to the previous research, these findings nevertheless support both, theoretically and practically, the relevance and topicality of research in this field. First, this paper provides a theoretical basis for further investigations that focus on product involvement and second, it establishes a valuable practical instrument to segment and categorize customers within a multichannel environment

A Diesel Engine Model for Dynamic Drive Cycle Simulations

The development and implementation of a diesel engine combustion system simulation model is described. The model is a crank angle based combustion model, which uses the conditions in the intake and exhaust manifolds together with the fuel injection signal from the engine control unit to estimate the in-cylinder pressure throughout a complete combustion cycle. The model is implemented in Matlab. Furthermore, a Simulink coupling has been developed and implemented such that the combustion model can be connected directly to a Simulink mean value model of an engine air system. The coupling makes the combustion model act like a continuous source and a continuous sink in a mean value model. The coupling makes it possible to continuously simulate an engine in steady-state or transient operation, while the combustion model produces estimated cylinder pressure traces for each combustion cycle. This makes it possible to estimate fuel consumption and to couple the model with emission models which use the cylinder pressure or the rate of heat release as input. The model is developed, calibrated and verified using measured data from a 2.4 liter Volvo diesel engine, equipped with a turbocharger, an exhaust gas recirculation system, and a common rail injection system. The combustion model estimates IMEPnet with a correlation factor of 0.995 for the used data. The simulation time is in the range between 1 and 25 milliseconds for one combustion cycle on a standard computer, depending on the implementation

Variation of moose (Alces alces) damage to Scots pine (Pinus sylvestris) in young forest stands

Forest damage by moose is an important issue in Swedish forest and wildlife management. This study aimed at understanding the variation of moose (Alces alces) damage to Scots pine (Pinus sylvestris). By plots in twenty-five young forest stands damage level, damage variation and stand characteristics were investigated through a survey in April 2005. On average 2.4% of the main stems showed recent damage (i.e. from the preceding winter) and 29.4% of the main stems had previous damage (from before preceding winter). The variation of damage within stands was negatively correlated with damage level. Compared to damage level, damage variation showed inversely correlations to several stand characteristics. These relationships were interpreted as an interaction mainly between the unique characteristics of a stand and moose browsing pattern. Such interactions determine the damage level, which in turn determines the predominant level of damage variation. The risk of a pine to be browsed, if its neighbour is browsed, is significantly higher than what expected from random browsing. That risk decreased linearly with increasing distance to the browsed pine. The patterns revealed are discussed in terms of how to decrease the share of damaged main stems in future stands and how to improve surveys and predictions of damage levels in young pine stands.I studien undersöktes variationen av stamskador på tall (Pinus sylvestris) vilka orsakats av älgens (Alces alces) vinterbete i 0,5-3 m höga ungskogsbestånd. Genom provytor studerades beståndsegenskaper, skadenivåer och skadors variation inom 25 ungskogsbestånd. Dessutom undersöktes skaderiskerna på slumpmässigt valda tallar och deras närmsta tallgranne. I genomsnitt hade 2,4 % av huvudstammarna skador som uppkommit under den senaste vintern (färska skador) och 29,4 % av huvudstammarna hade skador som uppkommit vid tidigare tillfälle (äldre skador). Studien visar också att det beräkningssätt som används för att bestämma skadenivå har stor betydelse för utfallet. Skadornas variation inom bestånden var signifikant negativt korrelerade med skadenivån, d.v.s. ju mera skador desto jämnare var skadorna fördelade över bestånden. Enligt teorier om växt - växtätarsamspel är det en interaktion mellan älgens beteende och miljöns egenskaper som bestämmer älgens betesmönster. I den här studien kartlades beståndens egenskaper för att få en uppfattning om denna interaktion. De speciella egenskaper som varje bestånd har antas påverka skadenivån, vilken i sin tur i hög grad tycks styra variationen på skadorna. De beståndsegenskaper som gav tydligast uttryck för detta var trädhöjd och täthet av begärligare lövträd än björk, vilka båda hade en signifikant positiv korrelation med variationen på de äldre skadornas fördelning inom bestånden. När en tall är granne till en betad tall ökas risken signifikant att den också skall vara betad, om man jämför med risken hos en slumpmässigt vald tall. Enligt den här studien ökar denna risken linjärt med närheten till den betade tallgrannen, sett över en säsong av vinterbete. Skadenivån var den faktor som till största delen påverkade skadornas variation. Kunskapen om det sambandet kan användas i framtida arbete för att angripa problem med älgskador på tall. Uppsatsens resultat diskuteras med avseende på, dels utvecklingen av inventeringsmetoder och prognoser för skador, dels om man med skötselmetoder kan minska andelen skadade huvudstammar i bestånd

Correlations between microstructure and Q-factor of tunable thin film bulk acoustic wave resonators

Correlations between microstructure and Q-factor of tunable solidly mounted Ba(0.25)Sr(0.75)TiO(3) (BSTO) thin film bulk acoustic wave resonators are studied using analysis of test structures prepared at different growth temperatures of the BSTO films varying in the range 450-650 degrees C. The observed changes in the Q-factor with growth temperature are correlated with related changes in microstructure, including the grain size, texture misalignment, interfacial amorphous layer, surface roughness, and deterioration of the Bragg reflector layers. The correlations are established through analysis of corresponding extrinsic acoustic loss mechanisms, including Rayleigh scattering at localized defects, acoustic attenuation by amorphous layer, generation of the shear waves leaking into the substrate, waves scattering by surface roughness, and resonance broadening by local thickness variations. It is shown that the waves scattering by surface roughness at the BSTO film interfaces is the main loss mechanism limiting the Q-factor of the BSTO thin film bulk acoustic wave resonators. (C) 2011 American Institute of Physics. [doi:10.1063/1.3626939

Sheaf theory for stacks in manifolds and twisted cohomology for S^1-gerbes

This is the first of a series of papers on sheaf theory on smooth and topological stacks and its applications. The main result of the present paper is the characterization of the twisted (by a closed integral three-form) de Rham complex on a manifold. As an object in the derived category it will be related with the push-forward of the constant sheaf from a S^1-gerbe with Dixmier-Douady class represented by the three-form. In order to formulate and prove this result we develop in detail the foundations of sheaf theory for smooth stacks.Comment: 39 pages, v2 typos corrected and references added. v3 confusion in 2.2.5 cleaned u

Adhesion layer-bottom electrode interaction during BaxSr1−xTiO3 growth as a limiting factor for device performance

Changes in bottom electrode morphology and adhesion layer composition upon deposition of Ba_xSr_1-xTiO₃ (BSTO) at elevated temperatures have been found, which have a negative impact on acoustic wave resonator device performance. The difference between nominal and actual adhesion layer composition are explained by grain boundary diffusion of Ti or W and their oxidation by in-diffusing oxygen, which leads to an increased interface roughness between the Pt bottom electrode and the BSTO. It is shown, that room-temperature deposited TiO₂ diffusion barriers fail to protect against Ti oxidation and diffusion. Also W adhesion layers are prone to this phenomenon, which limits their ability to act as high temperature resistant adhesion layers for bottom electrodes for ferroelectric thin films

Potatoes specific gravity and boiling properties in view of growing location and variety

The boiling properties are an important quality issue of the potato. In order to obtain adequate boiling properties the growth of the potato needs to be controlled and interrupted at the right time. However, it is difficult to determine when to stop the growth. Specific gravity can easily be measured and can sometimes be used as a tool for estimating the boiling properties. This report discusses different aspects of the specific gravity of the potato and how it can be used as a tool to determine the appropriate time for vine killing. The study includes a literature study and a practical field trial. The field trial has been conducted on five different farms situated in the southern parts of Sweden and includes three different varieties. Two sites were selected at each field along with the farmers, one site with low field capacity representing the dry site and one with higher field capacity, representing the wet site. The aim of this study was to get a better understanding of how the specific gravity can vary within the field, but also to evaluate the potato hydrometer as a tool for finding the right time to stop the growth of the potato crop. Water is the most important factor influencing the growth of most plants. Both water and nutrient supply will affect the boiling properties and specific gravity of potatoes. Potato is a crop that requires a good access to water and nutrient. Nitrogen is the nutrient that has the greatest impact on the specific gravity, quality and yield of potato crop. The specific gravity is closely liked to the maturation of the potato plant. The results from this study show that there can be great differences in boiling properties within a field. However, sometimes fields that vary in quality and yield can have a uniform development of the specific gravity. It seems like different varieties has different tendencies to develop a uniform specific gravity. King-Edward is a variety which tends to have relatively uneven specific gravity within the field, while the specific gravity in Bintje and Fakse seems less influenced on external factors such as uneven water supply. The results from this study indicate that the specific gravity decreases after vine killing. The potato hydrometer can be efficiently used in some cases as a tool for estimating the boiling properties of the potato.Kokkvalitet är en viktig kvalitetsegenskap på potatis. För att uppnå en önskad kokkvalitet behöver odlaren information för att styra sina insatser och tiden för dessa. Den insats som kan vara svårast att hitta är rätt tidpunkt för blastdödning. Mätning av den specifika vikten kan vara ett hjälpmedel för att ta beslut om denna tidpunkt då mätningen kan ge goda vägledningar hur mognaden är på potatisen. Vi har gjort en studie på potatis och dess utveckling av specifik vikt på fem olika gårdar i Skåne. Tillsammans med odlarna valdes 2 provplatser per fält, en torrare och en mer vattenhållande plats. Detta för att studera eventuella skillnader i kvalitet. Målet med denna studie är att få en större förståelse för hur kvaliteten kan variera inom ett fält. Anledningen är att potatisindustrin ställer höga krav på potatis av jämn kvalitet. Ett av de stora kvalitetskraven är kokkvalitet som innebär att potatisen inte får vara blötkokande eller sönderfallande. Vi har valt att avgränsa oss till att studera hur kokegenskaper och specifik vikt påverkas beroende på växtplatsens vattenhållande förmåga. Arbetet omfattar även en utvärdering av sjunkmetoden som är ett hjälpmedel för att fastställa potatisens specifika vikt och därigenom lämplig blastdödningstidpunkt. Potatis är en gröda vars krav på vatten och växtnäring är mycket stort. Anledningen till det stora vattenbehovet är bland annat att potatis har en stor bladyta och ett grunt rotsystem. Även växtnäringsämnen har stor betydelse för potatisens kvalitet och kvantitet. Kväve är det ämne som har störst inverkan på den specifika vikten och därmed kokegenskaperna. Den specifika vikten är nära kopplad till potatisplantans mognad. I resultatet har vi sett att fälten med King-Edward inte har en lika jämn och stabil torrsubstansutveckling som Fakse och Bintje. Tendensen överlag är att specifika vikten sjunker något mellan blastdödning och skörd. Vi har upplevt att ett fält kan ha jämn specifik vikt trots stor kvalitets- och skördevariation. Potatishydrometern har vi uppfattat som ett tillförlitligt instrument för bedömning av specifik vikt. För att skaffa sig ett bra och tillförlitligt beslutsunderlag bör man ta flera prover i fältet, för att upptäcka lokala variationer. Man bör inte slå samman olika platser vid mätning med potatishydrometern eftersom man då missar variationen inom fältet. Provtagningsintensiteten bör vara hög i slutet av odlingssäsongen, eftersom mognaden kan gå fort. Under en period är det inte ovanligt att den specifika vikten stiger med över en enhet om dagen på potatishydrometerns skala