424 research outputs found
The Parameter-Less Self-Organizing Map algorithm
The Parameter-Less Self-Organizing Map (PLSOM) is a new neural network
algorithm based on the Self-Organizing Map (SOM). It eliminates the need for a
learning rate and annealing schemes for learning rate and neighbourhood size.
We discuss the relative performance of the PLSOM and the SOM and demonstrate
some tasks in which the SOM fails but the PLSOM performs satisfactory. Finally
we discuss some example applications of the PLSOM and present a proof of
ordering under certain limited conditions.Comment: 29 pages, 27 figures. Based on publication in IEEE Trans. on Neural
Network
Graphics Hardware Implementation of the Parameter-Less Self-Organising Map
This paper presents a highly parallel implementation of a new type of Self-Organising Map (SOM) using graphics hardware. The Parameter-Less SOM smoothly adapts to new data while preserving the mapping formed by previous data. It is therefore in principle highly suited for interactive use, however for large data sets the computational requirements are prohibitive. This paper will present an implementation on commodity graphics hardware which uses two forms of parallelism to signiÂŻcantly reduce this barrier. The performance is analysed experi- mentally and algorithmically. An advantage to using graphics hardware is that visualisation is essentially free", thus increasing its suitability for interactive exploration of large data sets
Active Audition for Robots using Parameter-Less Self-Organising Maps
How can a robot become aware of its surroundings? How does it create its own subjective, inner representation of the real world, so that relationships in the one are reflected in the other? It is well known that structures analogous to Self-Organising Maps (SOM) are involved with this task in animals, and this thesis undertakes to explore if and how a similar approach can be success- fully applied in robotics. In order to study the environment-to-abstraction mapping with a minimum of guidance from directed learning and built-in design assumptions, this thesis examines the active audition task in which a system must determine the direction of a sound source and orient towards it, both in horizontal and vertical direction. Previous explanations of directional hearing in animals, and the implementation of directional hearing algorithms in robots have tended to focus on the two best known directional clues; the intensity and time differences. This thesis hypothesises that it is advantageous to use a synergy of a wider range of metrics, namely the phase and relative intensity difference. A solution to the active audition problem is proposed based on the Parameter- Less Self-Organising Map (PLSOM), a new algorithm also introduced in this thesis. The PLSOM is used to extract patterns from a high-dimensional input space to a low-dimensional output space. In this application the output space is mapped to the correct motor command for turning towards the source and focusing attention on the selected source by filtering unwanted noise. The dimension-reducing capability of the PLSOM enables the use of more than just two directional clues for computation of the direction. This thesis presents the new PLSOM algorithm for SOM training and quantifies its performance relative to the ordinary SOM algorithm. The mathematical correctness of the PLSOM is demonstrated and the properties and some applications of this new algorithm are examined, notably in automatically modelling a robot's surroundings in a functional form: Inverse Kinematics (IK). The IK problem is related in principle to the active audition problem - functional rather than abstract representation of reality - but raises some new questions of how to use this internal representation in planning and execution of movements. The PLSOM is also applied to classification of high-dimensional data and model-free chaotic time series prediction. A variant of Reinforcement Learning based on Q-Learning is devised and tested. This variant solves some problems related to stochastic reward functions. A mathematical proof of correct state-action pairing is devised
Timing and conditions modify the effect of structure liming on clay soil
Two dates (early, normal) for application and incorporation of structure lime to clay soil were examined at four field sites, to test whether early liming had more favourable effects on aggregate stability. Aggregate size distribution measurements revealed a finer tilth at the early liming date (20 August) than the normal date (14 September). Aggregate stability estimated one year later, using as a proxy turbidity in leachate from 2â5 mm aggregates subjected to two simulated rainfall events, was significantly improved (11% lower turbidity) with early compared with normal liming date. Three years after structure liming, soil structural stability measurements on lysimeters (15 cm high, inner diameter 18 cm) subjected to repeated simulated rainfall events showed no significant differences in turbidity in leachate between the early and normal liming dates. However, there was a strong interaction between liming date and site indicating different reactions at different sites. Our results suggest that early spreading and incorporation can improve the success of structure liming, but only if soil conditions are favourable
Ritualen och dess potentiella anvÀndning i organisationer
The essay's aim is to create an understanding for the act; ritual, and the functions or possible functions in an organisation. Many of the functions attribute to rituals lie in the ritual's double function. A ritual can function both as a practical/functional and a symbolic act. The functionality in a ritual doing is not depending of the "symbolic meaning". The functional value exists there always. The symbolic value that exists in a ritual is linked to the people's feelings and how he or she considers the ritual. This worth or symbolic function is of course different to different people and therefore the ritual influences people differently.
There is no doubt that it's possible to use rituals in organisations where they occur in a quite comprehensive degree. A better understanding for the ritual value and how to systematically plan the use of rituals, is something that this essay might contribute to.Uppsatsens syfte Àr att skapa en förstÄelse för handlingen; ritual och hur den fungerar/kan
fungera i en organisation. Mycket av den funktion som tillskrivs ritualen ligger i ritualens
dubbla funktion. En rituellhandling kan fungera bÄde som en praktisk/funktionell och en
symbolisk handling. Det funktionella vÀrdet som en rituellhandling har, Àr inte beroende utav
handlingens symbolik det funktionella stoffet finns alltid dÀr. Det symboliska vÀrdet som
finns i en ritual Àr kopplat till mÀnniskans/ritualdeltagarens kÀnslor och hur han eller hon
uppfattar ritualen. Detta vÀrde Àr givetvis olika stort och de pÄverkar mÀnniskor olika mycket.
Att det Àr möjligt att anvÀnda ritualer i organisationer Àr det inget tvivel om, dÄ det
förekommer i ganska omfattande grad. Dermot kan det vara sÄ att ritualer anvÀnds ganska
okritiskt. En bÀttre förstÄelse för ritualen och hur den systematiskt skulle kunna planeras, Àr
nÄgot som den hÀr uppsatsen möjligen kan bidra till
Implementering av ledningsbeslut i lantbrukskooperativ
Företagsledningar fattar beslut, i syfte att möta eller skapa förÀndringar, dessa pÄverkar ofta hela organisationen. Efter att ledningen fattat ett beslut mÄste beslutet verkstÀllas pÄ ett eller annat sÀtt, denna verkstÀllningsprocess kallas för implementering. MÄnga beslut som fattas av ledningen misslyckas under dess implementering i organisationen. UtifrÄn denna verklighet Àr
det intressant att studera implementeringsprocesser. Detta har gjorts pÄ olika organisationer men inte i nÄgot lantbrukskooperativ tidigare.
Denna studie syftar till att ingÄende redogöra för implementeringen av ett ledningsbeslut som genomförts i lantbrukskooperativ. Vidare syftar studien till att ge information om vad som pÄverkade (pÄverkar) implementeringsprocessen. Det sista delsyftet Àr att jÀmföra
implementeringsprocessen i kooperativa företag med implementeringsprocesser i ett aktiebolag.
Studien har genomförts som en kvalitativ fallstudie pÄ Mellanskog ekonomisk förening i Uppsala. DÀr har tvÄ personer intervjuats, en frÄn organisationens ledning och en person som arbetat med att verkstÀlla beslutet.
Resultaten visar att ett medelstort lantbrukskooperativ med nÀra relation till sin Àgarorganisation, likt Mellanskog, utformas implementeringsprocesser med mycket stora
anstrÀngningar i förankringsarbetet. Detta i syfte att skapa acceptans i: dels den interna operativa organisationen och dels i Àgarorganisationen.
Implementeringsresultaten och implementeringsprocesserna pÄverkas av en rad faktorer i kooperativa företag, troligen pÄverkar organisationskulturen och Àgarorganisationen
processen mest i lantbrukskooperativ likt Mellanskog. Detta gör att kooperativa organisationer behöver grundligare och lÀngre (frÄn ledningen mÀtt) förankringsprocesser.
Det finns ett antal skillnader mellan implementeringar i kooperativ och i aktiebolag. Dessa ligger frÀmst i att kooperativet mÄste förankra besluten lÀngre ut frÄn ledningen, att organisationskulturen Àr mer pÄtaglig och ofta kan fungera som ett stöd. Dessa faktorer leder
(troligen) till att ledningen för ett kooperativ, likt Mellanskog, utvecklar en inkrementell implementeringsprocess, nÄgot som inte Äterfinns i aktiebolagsledningarnas agerande. Det finns Àven likheter, frÀmst i implementerarnas behov av resursflöden till implementeringsprojekten
Novel aspects of the molecular biology of gastrointestinal stromal tumors
The gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor in the
gastrointestinal tract (GI). Historically, these tumors were commonly mistaken for myogenic and
neurogenic masses, and then eventually came to be recognized as a distinct type of soft-tissue
sarcoma through ultrastructural findings and specific immunomarkers. GISTs can arise anywhere
along the GI tract, and are believed to originate from or share a common progenitor with the
interstitial cell of Cajal. The majority of GISTs carry activating KIT or PDGFRA mutations,
which form the molecular basis for the successful tyrosine kinase inhibitor therapy. Although
genetic discoveries and treatment advances have greatly improved clinical outcomes, the
significance of GIST neuroendocrine phenotype, the role of the relatively newly identified
DOG1, and the impact of regional imatinib pharmacodynamics remain obscure. The aim of the
overall thesis was to explore functional aspects of the human GIST biology.
Evaluation of the presence of functional GIST cell stimulus-secretion coupling demonstrated an
intact intracellular Ca2+-signaling pathway and an active ATP release that is dependent on [Ca2+]e
levels and is augmentable by pharmacological stimuli. (Paper I)
The existence and composition of a putative GIST secretome was assessed by shotgun
proteomics. The findings demonstrate that GIST cells contain a secretome signature made up of
classically and non-classically released proteins. The protein subsets and appurtenant functional
clustering varied in the presence of drug stimulation. The types of released proteins, which
significantly increased through cell stimulation, were consistent with the types of proteins found
in other cancers. Moreover, the secretome overlapped extensively with exosomal proteins.(Paper II)
A protocol to measure intracellular imatinib levels was developed for use in both in vitro and in
vivo systems of GIST cells. The liquid-liquid extraction LC-MS TOF-based protocol offered a
reliable way to determine intracellular imatinib levels with high recovery, good linearity, and low
limit of detection, in both the experimental and clinical settings. The imatinib uptake differed
between imatinib-sensitive and imatinib-resistant cell lines, and accumulated in tumors from
three patients, with large intra- and inter-tumoral variations. (Paper III)
The functional significance of DOG1 in GIST cells was addressed. DOG1 have different
subcellular localizations in imatinib-sensitive and imatinib-resistant GIST cells. Specific
inhibitors or activators modulated the DOG1 activity efficaciously. The overall effect on GIST
cell viability and proliferation was small, but DOG1 inhibition induced late apoptosis among a
small proportion of early apoptotic imatinib-resistant GIST cells. (Paper IV
UtvÀrdering av utbildning om attityder och beteenden inom ETTdemo-projektet
This is a thesis report from SLU in Skinnskatteberg, the Swedish university of agricultural sciences. This study is an evaluation of a course in attitudes and behavior for participants of the ETT- project led by Skogforsk, the forestry research institute of Sweden. They do research for the benefit of Swedish forestry. The ETT-project is a project where there are both 74 tons ST-trucks and 90 tons ETT-trucks in test on the public roads. This study is concentrated on the ST-trucks and their drivers, company owners and logistics managers.
The evaluation is done by interviews with the various participants. The interviews are made with the drivers in the truck, while the company owners have been interviewed at the local café. The logistics managers have been interviewed by phone.
Most of the respondents are pleased with the course, but there are a few things they think are missing or are unnecessary. That means that the course has been given a good review. The subjects that the participators think are missing are mostly facts about the truck and its characteristics.
The most important result from the study is that the drivers consider themselves very good in their profession. They are aware of their role as ambassadors for the brand and the project. They consider themselves as role models for other drivers. This means that the goal with the course has been reached
Improving lean design of production systems by visualization support
The design process of production systems is complex with many different aspects to consider for efficiently developing and installing an effective system. Important success factors during the design process are typically the abilities to identify and manage risks, develop mitigation plans, and conduct timely proactive problem solving. The work reported in this paper is part of research addressing methods for how the design process can be supported by using virtual representations of the factory environments captured with 3D laser scanning. This support is evaluated in an industrial study of one industrialization project in the manufacturing industry. The industrialization project follows the process to design layout, work places, and plan for installation of new equipment to create a production system within a refurbished shop floor area. The area will include CNC machining centers, welding stations, product inspection, product cleaning, and material handling. 3D laser scanning is used to provide an accurate and realistic virtual representation of the current shop floor area. This virtual representation is combined with 3D CAD models of the new machining centers and other equipment to provide a realistic visualization of the planned production system. The research approach and its questions investigate the benefits of combining the lean principles to design and development of production systems using a realistic visualization, which include systematic risk analysis and problem solving as important activities. The result shows that visualization support gave a great advantage to identify the possible risks and problems, which resulted in higher confidence and substantial timesaving in planning and execution of the industrialization project
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