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Abstract: Collective risks permeate society, triggering social dilemmas in which working toward a common goal is impeded by selfish interests. One such dilemma is mitigating runaway climate change. To study the social aspects of climate-change mitigation, we organized an experimental game and asked volunteer groups of three different sizes to invest toward a common mitigation goal. If investments reached a preset target, volunteers would avoid all consequences and convert their remaining capital into monetary payouts. In the opposite case, however, volunteers would lose all their capital with 50% probability. The dilemma was, therefore, whether to invest one's own capital or wait for others to step in. We find that communicating sentiment and outlook helps to resolve the dilemma by a fundamental shift in investment patterns. Groups in which communication is allowed invest persistently and hardly ever give up, even when their current investment deficits are substantial. The improved investment patterns are robust to group size, although larger groups are harder to coordinate, as evidenced by their overall lower success frequencies. A clustering algorithm reveals three behavioral types and shows that communication reduces the abundance of the free-riding type. Climate-change mitigation, however, is achieved mainly by cooperator and altruist types stepping up and increasing contributions as the failure looms. Meanwhile, contributions from free riders remain flat throughout the game. This reveals that the mechanisms behind avoiding collective risks depend on an interaction between behavioral type, communication, and timing.
Keywords: social dilemma, free riding, climate change, negotiation, group size, COVID-19
Published in DKUM: 07.01.2025; Views: 0; Downloads: 2
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Abstract: Islets of Langerhans are multicellular microorgans located in the pancreas that play a central role in whole-body energy homeostasis. Through secretion of insulin and other hormones they regulate postprandial storage and interprandial usage of energy-rich nutrients. In these clusters of hormone-secreting endocrine cells, intricate cell-cell communication is essential for proper function. Electrical coupling between the insulin-secreting beta cells through gap junctions composed of connexin36 is particularly important, as it provides the required, most important, basis for coordinated responses of the beta cell population. The increasing evidence that gap-junctional communication and its modulation are vital to well-regulated secretion of insulin has stimulated immense interest in how subpopulations of heterogeneous beta cells are functionally arranged throughout the islets and how they mediate intercellular signals. In the last decade, several novel techniques have been proposed to assess cooperation between cells in islets, including the prosperous combination of multicellular imaging and network science. In the present contribution, we review recent advances related to the application of complex network approaches to uncover the functional connectivity patterns among cells within the islets. We first provide an accessible introduction to the basic principles of network theory, enumerating the measures characterizing the intercellular interactions and quantifying the functional integration and segregation of a multicellular system. Then we describe methodological approaches to construct functional beta cell networks, point out possible pitfalls, and specify the functional implications of beta cell network examinations. We continue by highlighting the recent findings obtained through advanced multicellular imaging techniques supported by network-based analyses, giving special emphasis to the current developments in both mouse and human islets, as well as outlining challenges offered by the multilayer network formalism in exploring the collective activity of islet cell populations. Finally, we emphasize that the combination of these imaging techniques and network-based analyses does not only represent an innovative concept that can be used to describe and interpret the physiology of islets, but also provides fertile ground for delineating normal from pathological function and for quantifying the changes in islet communication networks associated with the development of diabetes mellitus.
Keywords: pancreatic islets, beta cells, calcium imaging, intercellular communication, functional networks, multilayer networks
Published in DKUM: 20.12.2024; Views: 0; Downloads: 3
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Abstract: Analiza stroškov življenjskega cikla (v nadaljevanju: LCCA ali analiza LCC) se v procesih, ki se izvajajo v skladišču, ne uporablja pogosto. Vendar lahko pričakujemo, da bi v prihodnosti postala vse pomembnejša, glede na to, da učinkovito načrtovanje in vrednotenje stroškov prinaša podjetjem velike prednosti. Metoda ocenjevanja stroškov skozi celoten življenjski cikel omogoča načrtovanje in spremljanje stroškov, kar predstavlja ključni pomen pri izbiri med več različnimi možnostmi. Čeprav se analiza LCC ne uporablja pogosto v skladiščnem sektorju, lahko na podlagi literature, ki se nanaša večinoma na sektor gradbeništva, ugotovimo, da obstaja velik potencial za uporabo analize tudi v sektorju skladiščenja. Dejansko bi jo lahko uporabili pri katerikoli uvedbi novih sredstev v skladišče ali celo pri gradbi novega skladišča. Pri analizi stroškov življenjskega cikla je pomembno upoštevati vse faze načrtovanja stroškov, od začetnih, inicialnih stroškov investicije do končne odstranitve sredstev na koncu življenjskega cikla in stroškov, ki potencialno lahko nastanejo pri tem postopku. V prihodnosti lahko pričakujemo, da se bo metoda LCCA več uporabljala v skladiščnem sektorju, saj podjetniki vedno bolj prepoznavajo pomen dolgoročnih prihrankov in trajnostnega poslovanja.
Keywords: skladišče, komisioniranje, analiza stroškov življenjskega cikla, življenjski cikel investicije, ocenjevanje stroškov
Published in DKUM: 17.12.2024; Views: 0; Downloads: 5
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Abstract: In the past years various methods have been developed to estimate high-resolution solar potential in urban areas, by simulating solar irradiance over surface models that originate from remote sensing data. In general, this requires discretisation of solar irradiance models that estimate direct, reflective, and diffuse irradiances. The latter is most accurately estimated by an anisotropic model, where the hemispherical sky dome from arbitrary surface’s viewpoint consists of the horizon, the circumsolar and sky regions. Such model can be modified to incorporate the effects of shadowing from obstruction with a view factor for each sky region. However, state-of-the-art using such models for estimating solar potential in urban areas, only considers the sky view factor, and not circumsolar view factor, due to high computational load. In this paper, a novel parallelisation of solar potential estimation is proposed by using General Purpose computing on Graphics Processing Units (GPGPU). Modified anisotropic Perez model is used by considering diffuse shadowing with all three sky view factors. Moreover, we provide validation based on sensitivity analysis of the method’s accuracy with independent meteorological measurements, by changing circumsolar sky region’s half-angle and resolution of the hemispherical sky dome. Finally, the presented method using GPPGU was compared to multithreaded Central Processing Unit (CPU) approach, where on average a 70x computational speedup was achieved. Finally, the proposed method was applied over a urban area, obtained from Light Detection And Ranging (LiDAR) data, where the computation of solar potential was performed in a reasonable time.
Keywords: solar energy, solar potential, anisotropic diffuse irradiance, LiDAR, GPGPU
Published in DKUM: 17.12.2024; Views: 0; Downloads: 3
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Abstract: Diplomsko delo zajema predstavitev ukrepov pristojnih služb na področju državne cestne infrastrukture za odpravo posledic ujme, ki je avgusta 2023 prizadela Slovenijo. Poudarek je na aktivnostih za vzpostavitev prevoznosti v prvih mesecih po ujmi, saj je šlo za obseg, ki je močno presegal razpoložljive kapacitete upravljavca glavnih in regionalnih cest, Direkcije Republike Slovenije za infrastrukturo oziroma izvajalcev gospodarske javne službe rednega vzdrževanja državnih cest, koncesionarjev devetih območij. Od skoraj 6.000 km cest, s katerimi upravljavec upravlja, so bile različne posledice evidentirane kar na 1.800 km cest. Od tega je bilo v petek, 4. 8. 2023,  postavljenih 92 popolnih zapor in 98 delnih zapor (skupaj 190) v skupni dolžini 584 km državnih cest. V skrajnih razmerah, ki jih je povzročila ujma avgusta 2023, se je izkazalo, da je sistem odziva na izredne dogodke, ki ga je v skladu z veljavnimi predpisi ter koncesijskimi in internimi pogodbami vzpostavil upravljavec, ustrezen. Kot ustrezna se je pokazala tudi organiziranost gospodarske javne službe rednega vzdrževanja državnih cest kot koncesionirane storitve na posameznem zaokroženem geografskem območju. Pa vendar je bilo, v do sedaj največji naravni katastrofi, na tem področju moč odkriti tudi pomanjkljivosti. To je bilo predvsem pomanjkanje kadrovskih resursov in materialnih sredstev v okviru priprave optimalnih rešitev na terenu.
Keywords: ujma, vzpostavitev prevoznosti, glavne ceste, regionalne ceste
Published in DKUM: 12.12.2024; Views: 0; Downloads: 1
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