Academic literature on the topic 'Good Bandit'
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Journal articles on the topic "Good Bandit"
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Olson, Mancur. "Dictatorship, Democracy, and Development." American Political Science Review 87, no. 3 (1993): 567–76. http://dx.doi.org/10.2307/2938736.
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Under anarchy, uncoordinated competitive theft by “roving bandits” destroys the incentive to invest and produce, leaving little for either the population or the bandits. Both can be better off if a bandit sets himself up as a dictator—a “stationary bandit” who monopolizes and rationalizes theft in the form of taxes. A secure autocrat has an encompassing interest in his domain that leads him to provide a peaceful order and other public goods that increase productivity. Whenever an autocrat expects a brief tenure, it pays him to confiscate those assets whose tax yield over his tenure is less than their total value. This incentive plus the inherent uncertainty of succession in dictatorships imply that autocracies will rarely have good economic performance for more than a generation. The conditions necessary for a lasting democracy are the same necessary for the security of property and contract rights that generates economic growth.
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Sharaf, Amr, and Hal Daumé III. "Meta-Learning Effective Exploration Strategies for Contextual Bandits." Proceedings of the AAAI Conference on Artificial Intelligence 35, no. 11 (2021): 9541–48. http://dx.doi.org/10.1609/aaai.v35i11.17149.
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In contextual bandits, an algorithm must choose actions given ob- served contexts, learning from a reward signal that is observed only for the action chosen. This leads to an exploration/exploitation trade-off: the algorithm must balance taking actions it already believes are good with taking new actions to potentially discover better choices. We develop a meta-learning algorithm, Mêlée, that learns an exploration policy based on simulated, synthetic con- textual bandit tasks. Mêlée uses imitation learning against these simulations to train an exploration policy that can be applied to true contextual bandit tasks at test time. We evaluate Mêlée on both a natural contextual bandit problem derived from a learning to rank dataset as well as hundreds of simulated contextual ban- dit problems derived from classification tasks. Mêlée outperforms seven strong baselines on most of these datasets by leveraging a rich feature representation for learning an exploration strategy.
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Kano, Hideaki, Junya Honda, Kentaro Sakamaki, Kentaro Matsuura, Atsuyoshi Nakamura, and Masashi Sugiyama. "Good arm identification via bandit feedback." Machine Learning 108, no. 5 (2019): 721–45. http://dx.doi.org/10.1007/s10994-019-05784-4.
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Li, Youxuan. "Improvement of the recommendation system based on the multi-armed bandit algorithm." Applied and Computational Engineering 36, no. 1 (2024): 237–41. http://dx.doi.org/10.54254/2755-2721/36/20230453.
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In order to effectively solve common problems of the recommendation system, such as the cold start problem and dynamic data modeling problem, the multi-armed bandit (MAB) algorithm, the collaborative filtering (CF) algorithm, and the user information feedback are applied by researchers to update the recommendation model online and in time. In other words, the cold start problem of the recommendation system is transformed into an issue of exploration and utilization. The MAB algorithm is used, user features are introduced as content, and the synergy between users is further considered. In this paper, the author studies the improvement of the recommendation system based on the multi-armed bandit algorithm. The Liner Upper Confidence Bound (LinUCB), Collaborative Filtering Bandits (COFIBA), and Context-Aware clustering of Bandits (CAB) algorithms are analyzed. It is found that the MAB algorithm can get a good maximum total revenue regardless of the content value after going through the cold start stage. In the case of a particularly large amount of content, the CAB algorithm achieves the greatest effect.
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Agarwal, Mridul, Vaneet Aggarwal, Abhishek Kumar Umrawal, and Chris Quinn. "DART: Adaptive Accept Reject Algorithm for Non-Linear Combinatorial Bandits." Proceedings of the AAAI Conference on Artificial Intelligence 35, no. 8 (2021): 6557–65. http://dx.doi.org/10.1609/aaai.v35i8.16812.
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We consider the bandit problem of selecting K out of N arms at each time step. The joint reward can be a non-linear function of the rewards of the selected individual arms. The direct use of a multi-armed bandit algorithm requires choosing among all possible combinations, making the action space large. To simplify the problem, existing works on combinatorial bandits typically assume feedback as a linear function of individual rewards. In this paper, we prove the lower bound for top-K subset selection with bandit feedback with possibly correlated rewards. We present a novel algorithm for the combinatorial setting without using individual arm feedback or requiring linearity of the reward function. Additionally, our algorithm works on correlated rewards of individual arms. Our algorithm, aDaptive Accept RejecT (DART), sequentially finds good arms and eliminates bad arms based on confidence bounds. DART is computationally efficient and uses storage linear in N. Further, DART achieves a regret bound of Õ(K√KNT) for a time horizon T, which matches the lower bound in bandit feedback up to a factor of √log 2NT. When applied to the problem of cross-selling optimization and maximizing the mean of individual rewards, the performance of the proposed algorithm surpasses that of state-of-the-art algorithms. We also show that DART significantly outperforms existing methods for both linear and non-linear joint reward environments.
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Nouiehed, Maher, and Sheldon M. Ross. "A conjecture on the Feldman bandit problem." Journal of Applied Probability 55, no. 1 (2018): 318–24. http://dx.doi.org/10.1017/jpr.2018.19.
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Abstract We consider the Bernoulli bandit problem where one of the arms has win probability α and the others β, with the identity of the α arm specified by initial probabilities. With u = max(α, β), v = min(α, β), call an arm with win probability u a good arm. Whereas it is known that the strategy of always playing the arm with the largest probability of being a good arm maximizes the expected number of wins in the first n games for all n, we conjecture that it also stochastically maximizes the number of wins. That is, we conjecture that this strategy maximizes the probability of at least k wins in the first n games for all k, n. The conjecture is proven when k = 1, and k = n, and when there are only two arms and k = n - 1.
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Fu, Lai. "Exploring the efficacy of Multi-Armed Bandit Algorithms in dynamic decision-making." Applied and Computational Engineering 93, no. 1 (2024): 141–48. http://dx.doi.org/10.54254/2755-2721/93/20240942.
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Abstract. Originating from the scenario of gambling machines in casinos, the Multi-Armed Bandit problem aims to optimize decision-making processes under limited resources to achieve maximum returns. This article delves into the principles, classifications, and practical applications of this problem. Researchers have proposed various algorithms to address this issue, including -greedy, Upper Confidence Bound, and Thompson Sampling, which have demonstrated good performance across different scenarios. The article further elaborates on the fundamental principles of Multi-Armed Bandit algorithms, encompassing the trade-off between exploration and exploitation, and provides a detailed classification of algorithms based on probability (e.g., -greedy) and value (e.g., UCB). These algorithms not only provide a framework for addressing real-world problems such as advertisement placement and resource allocation, but also possess significant theoretical value in the fields of machine learning and reinforcement learning. By balancing exploration and exploitation, Multi-Armed Bandit algorithms offer effective tools for making optimal decisions in uncertain environments, thus driving the development of related fields.
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Tran, Alasdair, Cheng Soon Ong, and Christian Wolf. "Combining active learning suggestions." PeerJ Computer Science 4 (July 23, 2018): e157. http://dx.doi.org/10.7717/peerj-cs.157.
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We study the problem of combining active learning suggestions to identify informative training examples by empirically comparing methods on benchmark datasets. Many active learning heuristics for classification problems have been proposed to help us pick which instance to annotate next. But what is the optimal heuristic for a particular source of data? Motivated by the success of methods that combine predictors, we combine active learners with bandit algorithms and rank aggregation methods. We demonstrate that a combination of active learners outperforms passive learning in large benchmark datasets and removes the need to pick a particular active learner a priori. We discuss challenges to finding good rewards for bandit approaches and show that rank aggregation performs well.
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Zhang, Hao, Yao Ma, and Masashi Sugiyama. "Bandit-Based Task Assignment for Heterogeneous Crowdsourcing." Neural Computation 27, no. 11 (2015): 2447–75. http://dx.doi.org/10.1162/neco_a_00782.
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We consider a task assignment problem in crowdsourcing, which is aimed at collecting as many reliable labels as possible within a limited budget. A challenge in this scenario is how to cope with the diversity of tasks and the task-dependent reliability of workers; for example, a worker may be good at recognizing the names of sports teams but not be familiar with cosmetics brands. We refer to this practical setting as heterogeneous crowdsourcing. In this letter, we propose a contextual bandit formulation for task assignment in heterogeneous crowdsourcing that is able to deal with the exploration-exploitation trade-off in worker selection. We also theoretically investigate the regret bounds for the proposed method and demonstrate its practical usefulness experimentally.
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Shi, Zheyuan Ryan. "AI for Social Good: Between My Research and the Real World." Proceedings of the AAAI Conference on Artificial Intelligence 35, no. 18 (2021): 15732–33. http://dx.doi.org/10.1609/aaai.v35i18.17863.
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AI for social good (AI4SG) is a research theme that aims to use and advance AI to improve the well-being of society. My work on AI4SG builds a two-way bridge between the research world and the real world. Using my unique experience in food waste and security, I propose applied AI4SG research that directly addresses real-world challenges which have received little attention from the community. Drawing from my experience in various AI4SG application domains, I propose bandit data-driven optimization, the first iterative prediction-prescription framework and a no-regret algorithm PROOF. I will apply PROOF back to my applied work on AI4SG, thereby closing the loop in a single framework.
Dissertations / Theses on the topic "Good Bandit"
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Fisher, Nicola Jane. "Deformation induced fluid flow and gold precipitation in banded iron-formation, Zimbabwe." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.238887.
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Sales, Márcio André dos Santos. "The geological setting of the Lamego banded iron-formation-hosted gold deposit, Quadrilátero Ferrífero district, Minas Gerais, Brazil." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/tape17/PQDD_0003/MQ28251.pdf.
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Wiberg, Steen Tobias. "Genetic relationships and origin of the Ädelfors gold deposits in Southeastern Sweden." Thesis, Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-67912.
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Ädelfors is situated ca 17 km east of Vetlanda, Jönköping County, in the N-S striking Trans-scandinavian igneous belt and is a part of the NE-SW striking 1.83-1.82 Ga Oskarshamn-Jönköping belt emplaced during a continental subduction towards the Svecofennian continental margin. The continental arc hosts the 1.83 Ga metasedimentary Vetlanda supergroup composed of foliated metagreywacke, metasandstone and metaconglomerate. The sequence is intercalated by mafic and felsic volcanites and hosts the Cu-Au-Fe-mines at Ädelfors. Ädelfors mining field consists of ca 330 mineralized quartz veins hosting both copper, gold and iron. The iron mines Nilsson’s iron mine (NFE) and Fe-mine (FE), the copper mine Kamelen (KM) and the gold mines Brånad’s mine (BR), Adolf Fredrik’s mine (AF), Old Kron mine (GKR), Old Kolhag’s mine (GKO), Thörn mine (TH), New Galon mine (NG), Stenborg’s mine (ST), Tysk mine (TG), Hällaskallen (HS) and Fridhem (FR) have been investigated to deduce a possible genetic relation between the veins and their origin. Sulfur isotope ratios have also been conducted on pyrite from KM, AF and FE. The veins can stucturally be divided into several groups. AF, GKR, ST, NG, TH and possibly NFE are striking 10-70° with a dip of 55-70°. BR, GKO and KM are striking 110-140° with a dip of 80-90° whereas TG and HS strike 90-110° dipping 85°. Fridhem, being distal to the other mines, strikes 70° and dips 80°. A chlorite-quartz-biotite-sericite-rich metapelite hosts the veins in all localities except; FR where a layered, beresitizised felsic volcanite rich in plagioclase, sericite, biotite and quartz hosts disseminated pyrite; and NFE, HS and NG which are hosted by a mafic tuffite. Quartz veins are mainly milky and equigranular, exceptions are FE with black pyrite-bearing quartz veins, cutting through the banded magnetite-metapelite and KM with its dynamically recrystallized quartz. Chlorite-, zeolite-, carbonate-, hematite-, amphibole-, kalifeldspar-, sericite-, biotite- and epidote alteration has been observed among the localities. The ore minerals are dominated by: fractured sub- to euhedral pyrite in cataclastic aggregates or selvage bands, interstitial chalcopyrite in pyrite, marcasite, pyrrhotite, gold and sporadic chalcopyrite diseased sphalerite and arsenopyrite. Previously not reported tetradymite, staurolite, galena and Ce-monazite have also been observed. Bismuthinite and tetradymite as inclusions in pyrite were observed in AF, GKR, FR and TG. Gold was observed in AF, BR, GKR and TG as inclusions in pyrite or quartz with a Au/Ag median of 78.41. HS distinguishes itself with Au/Ag ratios of 4.66-5.25. The trace element ratios in pyrite reveal two major types of pyrite. 1) found in FE and KM (pyrite type 1) with Co/Ni ratio of 10.94, Bi/Au of 1.79, Bi/S of 0.037, Au/Ag of 11.13, S/Se of 235.96 and As/S of 0.006. 2) found in NG, GKO, ST, TH, AF, NFE, HS, GKR, BR, FR, TG and as stringers in KM4 py1 pyrite type 2) with an average Co/Ni ratio of 5.26, Bi/Au of 1.95, Bi/S of 0.031, Au/Ag of 4.19, S/Se of 0 and As/S of 0. δ34S values strengthens this grouping as KM and FE has 1,3-2,6 ‰ and AF 3,6-3,8 ‰. The following geological interpretation has been concluded: The banded iron formation in FE is the earliest mineralization and was later fractured, emplacing quartz veins with pyrite of type 1. During this event, the Cu-vein in KM was also formed. A second generation of fractures, emplaced after the Småland granitoids formed, were filled with quartz and pyrite of type 2 at mesozonal depth. This is the main stage of gold mineralization and includes NG, GKO, ST, TH, AF, NFE, GKR, BR, FR and TG. During this event, pyrite of type 2 was added to KM, causing recrystallizing of the quartz. HS is possibly emplaced last or altered as it is more enriched in silver. Morphology, mineralogy, alterations, mineral chemistry and sulfur isotope signatures indicates an orogenic origin of the gold-rich quartz veins at Ädelfors as well as the copper-rich vein in KM.<br>Ädelfors ligger ca 17 km öster om Vetlanda, Jönköpings län, i det N-S strykande Transskandinaviska granit och porfyrbältet och är en del av det NÖ-SV strykande 1,83-1,82 Ga Oskarshamn-Jönköpingsbältet (OJB) bildad i en kontinental subduktionszon i kanten av den Svecofenniska kontinentalplattan. I denna kontinentalbåge ligger Vetlanda supergruppen som är en metasedimentär del av OJB bestående av starkt folierad 1,83 Ga metagråvacka, metasandsten och metakonglomerat med inlagringar av mafiska och felsiska vulkaniter. Ädelfors gruvfält består utav ca. 330 kvartsgångar förande mestadels guld men också koppar. Järnmineraliseringar i form av bandad järnmalm finns också i området. Geologin, mineralogin och pyritens kemiska sammansättning från järngruvorna Nilssons järngruva (NFE) och Fe-gruvan (FE), koppargruvan Kamelen (KM) och guldgruvorna Brånadsgruvan (BR), Adolf Fredriks gruva (AF), Gamla Krongruvan (GKR), Gamla Kolhagsgruvan (GKO), Thörngruvan (TH), Nya Galongruvan (NG), Stenborgs gruva (ST), Tyskgruvan (TG), Hällaskallen (HS) och Fridhem (FR) har undersökts för att finna eventuella genetiska likheter. Svavelisotopförhållande har fastställts för pyrit från AF, FE och KM. Strukturellt kan gångarna delas in i ett antal grupper. AF, GKR, ST, NG, TH och möjligtvis NFE stryker 10-70° och stupar 55-70°. BR, GKO och KM stryker 110-140° och stupar 80-90° medan TG och HS stryker 90-110° och stupar 85°. Fridhem stryker 70° och stupar 80°. En klorit-kvarts-sericit-biotitrik metapelit utgör värdbergarten i alla gruvor förutom; FR där den utgörs av en beresitiserad felsisk vulkanit rik på plagioklas, sericit, biotit och kvarts med disseminerad pyrit; och NFE, HS, NG vilka har en mafisk tuffitisk moderbergart. Kvartsgångarna är mjölkvita med undantag för FE:s svarta, pyritförande kvarts vilket uppträder som sprickfyllnad i den bandade järnmalmen och är senare bildad. Kvartsen i KM är starkt dynamiskt omkristalliserad. Svag till måttlig foliation är vanlig i sidoberget med undantag av stark foliation i TG och NFE, vilka är lokaliserade i förkastningssprickor med stark kloritförskiffring av värdbergarten. Klorit-, zeolit-, karbonat-, hematit-, amfibol-, kalifältspat-, sericit-, biotit- och epidotomvandling förekommer i majoriteten av lokalerna. Malmmineralen är dominerande sprött deformerad subhedral till euhedral pyrit som kataklastiska aggregat eller band, interstitiell kopparkis i pyrit, markasit, magnetkis, guld och sporadiskt kopparkissjuk zinkblände och arsenikkis. I det här arbetet har även tetradymit, staurolit, blyglans och Ce-monazit observerats. Bismutinit och tetradymit i form av inneslutningar i pyrit observerades i AF, GKR, FR och TG. Guld observerades i AF, BR, GKR och TG som inneslutningar i pyrit eller fritt i kvarts med Au/Ag medianvärde på 78,41, avvikande är HS med värden mellan 4,66-5,25. Förhållanden mellan spårelement i pyrit indikerar två typer av pyrit. Typ 1 funnen i FE och KM har följande värden: Co/Ni = 10,94, Bi/Au = 1,79, Bi/S = 0,037, Au/Ag = 11,13, S/Se = 235,96 och As/S = 0,006. Typ 2 funnen i NG, GKO, ST, TH, AF, NFE, HS, GKR, BR, FR, TG och som sliror i KM4 py1 har följande värden Co/Ni = 5,26, Bi/Au = 1,95, Bi/S = 0,031, Au/Ag = 4,19, S/Se = 0 and As/S = 0. δ34S värden styrker denna uppdelning där KM och FE har värdena 1,3-2,6 ‰ och AF 3,6-3,8 ‰. Den geologiska utvecklingen av fältet har tolkats som följande: FE-gruvans bandade järnmalm är den tidigaste mineraliseringen vilket följs utav uppsprickning och läkning av kvarts med pyrit typ 1 som också bildar kopparmineraliseringen KM. Senare sprickzoner efter Smålandsgraniternas intrusion läks av kvarts med pyrit typ 2 på mesozonalt djup vilket bildar NG, GKO, ST, TH, AF, NFE, GKR, BR, FR, TG och omkristalliserar och introducerar nya pyritsliror i kvartsen i KM. HS bildas möjligtvis sist eller har blivit omvandlad eftersom den är anrikad på silver. Morfologi, omvandlingar och svavelisotop-signaturer tyder på ett orogent ursprung för Ädelfors guldrika kvartsådror samt den kopparrika kvartsådern i KM.
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Tripp, Gerard I. "Structural geology and gold mineralisation of the Ora Banda and Zuleika districts, Eastern Goldfields, Western Australia." Thesis, Curtin University, 2000. http://hdl.handle.net/20.500.11937/169.
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Late-Archaean deformation at Ora Banda 69km northwest of Kalgoorlie, Western Australia, resulted in upright folds (D2), ductile shear zones (D3), and a regional-scale brittle-ductile fault network (D4). Early low-angle faults (D', D1), documented in the surrounding Coolgardie, Kambalda and Boorara Domains are not developed in the Ora Banda Domain, and the fabrics reflect only the latest ENE-WSW shortening event. The western limb of the regional-scale ESE- plunging Kurrawang syncline (D2), is truncated by the Zuleika Shear Zone (D3), a within- greenstone ductile shear zone located 10km southeast of Ora Banda. The shear zone has a much greater strike length (250km) than depth extent, as seismic imagery reveals a sharp truncation against a mid-crustal decollement at a depth of 6km-depth below surface. The Zuleika Shear Zone is a NW-SE trending band of anastomosing S-C mylonite zones formed in conjugate sets of NW- SE trending sinistral and N-S trending dextral shear zones. Widely distributed flattening strains and more restricted zones of non-coaxial shear in the Zuleika Shear Zone, suggest deformation-path partitioning typical of a transpressional tectonic environment. Latetectonic brittle-ductile faults (D4) cross-cut the Zuleika Shear Zone and surrounding greenstones, and hence are not Riedel structures or other lower order faults genetically related to the ductile shearing. Gold mineralisation of the Zuleika Shear Zone began during the ductile deformation (D3), continued through peak metamorphism that postdates the shearing, and finally ceased after the brittle-ductile faulting event (D4). Gold deposits are primarily located where brittle-ductile faults intersect the Zuleika Shear Zone.Brittle-ductile faults (D4), are developed in three principal structural orientations: N-S (dextral), NE-SW (dextral) and E-W (sinistral). These faults display mutual cross-cutting relationships and were formed synchronously during a single regional shortening event. The brittle-ductile fault network is developed unevenly over the region, being localised in packets of high fracture-density referred to as structural zones. The Ora Banda structural zone is an area of high density faulting in the vicinity of Ora Banda, composed of a network of interlinked faults in which alternating ductile and brittle conditions produced cataclasite, breccia and quartz vein systems overprinting mylonite and schistosity. Other areas of high fracture-density (eg. Grants Patch and Mount Pleasant structural zones), are located within the NW-SE trending Ora Banda mafic sequence and spaced at 10km intervals to the southeast of Ora Banda. This spatial periodicity of high fracturedensity within the mafic sequence may have developed as a result of layer-parallel extension during ENE- WSW regional shortening. Gold deposits are concentrated in the Ora Banda, Grants Patch and Mount Pleasant structural zones. Gold distribution within the Ora Banda structural zone traces out the distribution of brittle-ductile faults, indicating that the fault network was the major pathway for fluid flow during mineralisation. Hydrothermal minerals are integral components of fault fabrics within the structural zone, and textures indicate that the faults were formed under conditions of high fluid pressure and, for much of the deformation, may have been fluid-generated.At Ora Banda the Enterprise gold deposit (40 tonnes Au) highlights the control of mesoscopic- scale fractures on gold distribution. On aeromagnetic imagery, the Enterprise fault zone appears as a narrow fault structure, but at a mesoscopic-scale, it is a broad zone of interlinked brittle-ductile faults and quartz veins. Fabrics developed in the layered, differentiated dolerite host rocks of the Enterprise fault zone, range from cataclasite to banded mylonite with a major component of net- veined breccia (mesofracturing). Kinematic analyses of fault slip lineations reveal an 055 directed (ENE-WSW) maximum shortening axis during brittle-ductile faulting. Microfabrics of the faults show extensive recrystallisation with significant post-deformation recovery that may be related to late to post - tectonic intrusion of the adjacent Lone Hand Monzogranite. Deformation mechanisms indicate that the D4 event occurred at a low-to-moderate temperature, in a low strain-rate enviromnent typical of mid to upper-greenschist facies crustal conditions. Gold mineralisation in the Enterprise deposit is controlled by faults with high-grade shoot development at the intersection of faults and host rock contacts that may represent gradients in tensile rock-strength. Although gold distribution indicates that faults are a major control on mineralisation, at a microscopic-scale, the control is by a linked network of microfractures that pervades the host rocks.Fry analysis of gold deposits within the Ora Banda mafic sequence shows clustering into groups with about 10km spacing. Coincidence of high fracture-density zones and gold deposits in 1Okm spaced-corridors reveals the regional-scale nature of gold mineralisation within the brittle-ductile fault network. Fluid-pressure gradients generated by pressure release during high-density fracturing, may have effectively increased fluid-rock ratios by focussing of metamorphic fluids through these areas. The largest gold deposits in the Ora Banda mafic sequence are hosted by 060-090 trending brittle-ductile faults with dilational textures (hydraulic breccia), and minor evidence of slip with negligible offsets. The orientation of these structures is sub-parallel to the regional axis of maximum shortening, hence an environment of fluid overpressuring in the presence of a far-field stress system produced conditions where fluid pressure is greater than or equal to the combined minimum compressive stress and the tensile rock strength. Such conditions are conducive to multiple failure episodes with fluid-pressure cycling and transient permeability as a consequence of fault reactivation. Formation of the brittle-ductile fault network occurred as a result of a delicate balance between deviatoric stress and fluid pressure, hence incremental fault development contributed to, and was a consequence of, the gold mineralisation event.The geometric relations of shear zones, brittle-ductile faults and gold mineralised zones are similar across all scales of observation from regional to microscopic and are therefore fractal. Fractal geometry indicates that deformation and gold mineralisation are temporally and genetically associated, and this combined with the textural relationships of the gold ores indicates that the sites of gold deposition were not structurally prepared prior to mineralisation. Development of early ductile to later brittle-ductile structures indicates changing conditions of deformation typical of decreasing crustal depth, or a variation of strain rate with time. The lack of a significant change in orientation of the maximum shortening direction and continuance of gold mineralisation throughout ductile and brittle deformation events, implies that deformation was progressive during a bulk shortening that accompanied uplift of the crust.
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Tripp, Gerard I. "Structural geology and gold mineralisation of the Ora Banda and Zuleika districts, Eastern Goldfields, Western Australia." Curtin University of Technology, School of Applied Geology, 2000. http://espace.library.curtin.edu.au:80/R/?func=dbin-jump-full&object_id=11707.
Full textAbstract:
Late-Archaean deformation at Ora Banda 69km northwest of Kalgoorlie, Western Australia, resulted in upright folds (D2), ductile shear zones (D3), and a regional-scale brittle-ductile fault network (D4). Early low-angle faults (D', D1), documented in the surrounding Coolgardie, Kambalda and Boorara Domains are not developed in the Ora Banda Domain, and the fabrics reflect only the latest ENE-WSW shortening event. The western limb of the regional-scale ESE- plunging Kurrawang syncline (D2), is truncated by the Zuleika Shear Zone (D3), a within- greenstone ductile shear zone located 10km southeast of Ora Banda. The shear zone has a much greater strike length (250km) than depth extent, as seismic imagery reveals a sharp truncation against a mid-crustal decollement at a depth of 6km-depth below surface. The Zuleika Shear Zone is a NW-SE trending band of anastomosing S-C mylonite zones formed in conjugate sets of NW- SE trending sinistral and N-S trending dextral shear zones. Widely distributed flattening strains and more restricted zones of non-coaxial shear in the Zuleika Shear Zone, suggest deformation-path partitioning typical of a transpressional tectonic environment. Latetectonic brittle-ductile faults (D4) cross-cut the Zuleika Shear Zone and surrounding greenstones, and hence are not Riedel structures or other lower order faults genetically related to the ductile shearing. Gold mineralisation of the Zuleika Shear Zone began during the ductile deformation (D3), continued through peak metamorphism that postdates the shearing, and finally ceased after the brittle-ductile faulting event (D4). Gold deposits are primarily located where brittle-ductile faults intersect the Zuleika Shear Zone.<br>Brittle-ductile faults (D4), are developed in three principal structural orientations: N-S (dextral), NE-SW (dextral) and E-W (sinistral). These faults display mutual cross-cutting relationships and were formed synchronously during a single regional shortening event. The brittle-ductile fault network is developed unevenly over the region, being localised in packets of high fracture-density referred to as structural zones. The Ora Banda structural zone is an area of high density faulting in the vicinity of Ora Banda, composed of a network of interlinked faults in which alternating ductile and brittle conditions produced cataclasite, breccia and quartz vein systems overprinting mylonite and schistosity. Other areas of high fracture-density (eg. Grants Patch and Mount Pleasant structural zones), are located within the NW-SE trending Ora Banda mafic sequence and spaced at 10km intervals to the southeast of Ora Banda. This spatial periodicity of high fracturedensity within the mafic sequence may have developed as a result of layer-parallel extension during ENE- WSW regional shortening. Gold deposits are concentrated in the Ora Banda, Grants Patch and Mount Pleasant structural zones. Gold distribution within the Ora Banda structural zone traces out the distribution of brittle-ductile faults, indicating that the fault network was the major pathway for fluid flow during mineralisation. Hydrothermal minerals are integral components of fault fabrics within the structural zone, and textures indicate that the faults were formed under conditions of high fluid pressure and, for much of the deformation, may have been fluid-generated.<br>At Ora Banda the Enterprise gold deposit (40 tonnes Au) highlights the control of mesoscopic- scale fractures on gold distribution. On aeromagnetic imagery, the Enterprise fault zone appears as a narrow fault structure, but at a mesoscopic-scale, it is a broad zone of interlinked brittle-ductile faults and quartz veins. Fabrics developed in the layered, differentiated dolerite host rocks of the Enterprise fault zone, range from cataclasite to banded mylonite with a major component of net- veined breccia (mesofracturing). Kinematic analyses of fault slip lineations reveal an 055 directed (ENE-WSW) maximum shortening axis during brittle-ductile faulting. Microfabrics of the faults show extensive recrystallisation with significant post-deformation recovery that may be related to late to post - tectonic intrusion of the adjacent Lone Hand Monzogranite. Deformation mechanisms indicate that the D4 event occurred at a low-to-moderate temperature, in a low strain-rate enviromnent typical of mid to upper-greenschist facies crustal conditions. Gold mineralisation in the Enterprise deposit is controlled by faults with high-grade shoot development at the intersection of faults and host rock contacts that may represent gradients in tensile rock-strength. Although gold distribution indicates that faults are a major control on mineralisation, at a microscopic-scale, the control is by a linked network of microfractures that pervades the host rocks.<br>Fry analysis of gold deposits within the Ora Banda mafic sequence shows clustering into groups with about 10km spacing. Coincidence of high fracture-density zones and gold deposits in 1Okm spaced-corridors reveals the regional-scale nature of gold mineralisation within the brittle-ductile fault network. Fluid-pressure gradients generated by pressure release during high-density fracturing, may have effectively increased fluid-rock ratios by focussing of metamorphic fluids through these areas. The largest gold deposits in the Ora Banda mafic sequence are hosted by 060-090 trending brittle-ductile faults with dilational textures (hydraulic breccia), and minor evidence of slip with negligible offsets. The orientation of these structures is sub-parallel to the regional axis of maximum shortening, hence an environment of fluid overpressuring in the presence of a far-field stress system produced conditions where fluid pressure is greater than or equal to the combined minimum compressive stress and the tensile rock strength. Such conditions are conducive to multiple failure episodes with fluid-pressure cycling and transient permeability as a consequence of fault reactivation. Formation of the brittle-ductile fault network occurred as a result of a delicate balance between deviatoric stress and fluid pressure, hence incremental fault development contributed to, and was a consequence of, the gold mineralisation event.<br>The geometric relations of shear zones, brittle-ductile faults and gold mineralised zones are similar across all scales of observation from regional to microscopic and are therefore fractal. Fractal geometry indicates that deformation and gold mineralisation are temporally and genetically associated, and this combined with the textural relationships of the gold ores indicates that the sites of gold deposition were not structurally prepared prior to mineralisation. Development of early ductile to later brittle-ductile structures indicates changing conditions of deformation typical of decreasing crustal depth, or a variation of strain rate with time. The lack of a significant change in orientation of the maximum shortening direction and continuance of gold mineralisation throughout ductile and brittle deformation events, implies that deformation was progressive during a bulk shortening that accompanied uplift of the crust.
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Hammond, Napoleon Quaye. "The geochemistry of ore fluids and control of gold mineralization in banded iron-formation at the Kalahari Goldridge deposit, Kraaipan greenstone belt, South Africa." Thesis, Rhodes University, 2003. http://hdl.handle.net/10962/d1008370.
Full textAbstract:
The Kalahari Goldridge mine is located within the Archaean Kraaipan Greenstone Belt about 60 km SW of Mafikeng in the Northwestern Province, South Africa. Several gold deposits are located within approximately north - south-striking banded iron-formation (BIF). Current opencast mining operations are focused on the largest of these (D Zone). The orebody is stratabound and hosted primarily in the BIF, which consists of alternating chert and magnetite-chloritestilpnomelane-sulphide-carbonate bands ranging from mm to cm scale. The ore body varies in thickness from 15 to 45 m along a strike length of about 1.5 km. The BlF is sandwiched between a sericite-carbonate-chlorite schist at the immediate footwall and carbonaceous meta-pelites in the hanging-wall. Further west in the footwall, the schists are underlain by mafic meta-volcanic amphibolite. Overlying the hanging-wall carbonaceous metapeiites are schist units and meta-greywackes that become increasingly conglomeratic up the stratigraphy. Stilpnomelane-, chlorite- and minnesotaite-bearing assemblages in the BlFs indicate metamorphic temperatures of 300 - 450°C and pressures of less than 5 kbars. The BIF generally strikes approximately 3400 and dips from 60 to 75°E. Brittle-ductile deformation is evidenced by small-scale isoclinal folds, brecciation, extension fractures and boudinaging of cherty BIF units. Fold axial planes are sub-parallel to the foliation orientation with sub-vertical plunges parallel to prominent rodding and mineral lineation in the footwall. Gold mineralization at the Kalahari Goldridge deposit is associated with two generations of subhorizontal quartz-carbonate veins dips approximately 20 to 40°W. The first generation consists of ladder vein sets (Group lIA) preferentially developed in Fe-rich meso bands, whilst the second generation consists of large quartz-carbonate veins (Group lIB), which crosscut the entire ore body extending into the footwall and hanging-wall in places. Major structures that control the ore body are related to meso-scale isoclinal folds with fold axes subparallel to mineral elongation lineations, which plunge approximately 067°E. These linear structures form orthogonal orientation with the plane of the mineralized shallowdipping veins indicating stretching and development of fluid - focusing conduits. A second-order controlling feature corresponds to the intersection of the mineralized veins and foliation planes of host rock, plunging approximately 008°N and trending 341°. G0ld is closely associated with sulphides, mainly pyrite and pyrrhotite and to a lesser extent with bismuth tellurides, and carbonate gangue. The ore fluid responsible for the gold deposition is in the C-O-H system with increased CH₄ contents attributed to localized hydrolysis reaction between interbedded carbonaceous sediment and ore fluid. The fluid is characterized by significant C0₂ contents and low salinities below 7.0 wt % NaCl equivalent (averages of 3.5 and 3.0 wt % NaCl equivalent for the first and second episodes of the mineralization respectively) . Calculated values of f0₂. ranging from 10⁻²⁹·⁹⁸ to 10⁻³²·⁹⁶ bars, bracket the C0₂-CH₄ and pyrite-pyrrhotite-magnetite buffer boundaries and reveal the reducing nature of the ore fluid at deposition. Calculated total sulphur content in the ore fluid (mΣs), ranges from 0.011 to 0.018M and is consistent with the range (10⁻³·⁵ to 10⁻¹M) reported for subamphibolite facies ore fluids. The close association of sulphides with the Au and nature of the fluid also give credence that the Au was carried in solution by the Au(HS)₂ - complex. Extensive epigenetic replacement of magnetite and chlorite in BIF and other meta-pelitic sediments in the deposit by sulphides and carbonates, both on meso scopic and microscopic scales gives evidence of an interaction by a CO₂- and H₂S-bearing fluid with the Fe-rich host rocks in the deposit. This facilitated Au precipitation due to changes in the physico-chemical conditions of the ore fluid such as a decrease in the mΣs and pH leading to the destabilization of the reduced sulphur complexes. Local gradients in f0₂ may account for gold precipitation in places within carbonaceous sediments. The fineness of the gold grams (1000*Au/(Au + Ag) ranges from 823 to 921. This compares favourably with the fineness reported for some Archaean BIFhosced deposits (851 - 970). Mass balance transfer calculations indicate that major chemical changes associated with the hydrothermal alteration of BIF include enrichment of Au, Ag, Bi, Te, volatiles (S and CO₂), MgO, Ba, K and Rb but significant depletion of SiO₂ and minor losses of Fe₂O₃. In addition, anomalous enrichment of Sc (average, 1247%) suggests its possible use as an exploration tool in the ferruginous sediments in the Kraaipan greenstone terrane. Evidence from light stable isotopes and fluid inclusions suggests that the mineralized veins crystallized from a single homogeneous fluid source during the two episodes of mineralization under the similar physicochemical conditions. Deposition occurred at temperatures rangmg from 350 to 400°C and fluid pressures ranging from 0.7 to 2.0kbars. Stable isotope constraints indicate the following range for the hydrothermal fluid; θ¹⁸H₂O = 6.65 to 10.48%0, 8¹³CΣc = -6.0 to -8.0 %0 and 8³⁴SΣs = + 1.69 to + 4.0%0 . These data do not offer conclusive evidence for the source of fluid associated with the mineralization at the Kalahari Goldridge deposit as they overlap the range prescribed for fluid derived from devolatization of deep-seated volcano-sedimentary piles near the brittle-ductile transition in greenstone belts during prograde metamorphism, and magmatic hydrothermal fluids.<br>KMBT_363<br>Adobe Acrobat 9.54 Paper Capture Plug-in
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Ghalme, Ganesh Sambhaji. "Algorithms for Social Good in Online Platforms with Guarantees on Honest Participation and Fairness." Thesis, 2020. https://etd.iisc.ac.in/handle/2005/4573.
Full textAbstract:
Recent decades have seen a revolution in the way people communicate, buy products, learn new things, and share life experiences. This has spurred the growth of online platforms that enable users from all over the globe to buy/review/recommend products and services, ask questions and provide responses, participate in online learning, etc.
There are certain crucial requirements that are required to be satisfied by the online forums for ensuring their trustworthiness and sustainability. In this thesis, we are concerned with three of these requirements: social welfare maximization, honest participation by the users, and fairness in decision making. In particular, we address three contemporary problems in online platforms and obtain principled solutions that achieve social welfare maximization while satisfying honest participation and fairness of allocation. The three problems considered are set in the context of three different platforms: online review or Q&A forums, online discussion forums, and online search platforms. In each case, we develop an abstraction of the problem and solve it in its generality.
1) Ballooning Multi-armed Bandits.
In our first problem, we consider online platforms where the users are shown user generated content such as reviews on an e-commerce platform or answers on a Q&A platform. The number of reviews/answers increases over time. We seek to design an algorithm that quickly learns the best review/best answer and displays it prominently. We model this problem as a novel multi-armed bandit formulation (which we call ballooning bandits) in which the set of arms expands over time. We first show that when the number of arms grows linearly with time, one cannot achieve sub-linear regret. In a realistic special case, where the best answer is likely to arrive early enough, we prove that we can achieve optimal sublinear regret guarantee. We prove our results for best answer arrival time distributions that have sub-exponetal or sub-Pareto tails.
2) Strategy-proof Allocation of Indivisible Goods with Fairness Guarantees.
Second, we consider the problem of fairness in online search platforms. We view the sponsored ad-slots on these platforms as indivisible goods to be allocated in a fair manner among competing advertisers. We use envy-freeness up to one good (EF1) and maximin fair share (MMS) allocation as the fairness notions. The problem is to maximize the overall social welfare subject to these fairness constraints. We first prove under a single parameter setting that the problem of social welfare maximization under EF1 is NP-hard. We complement this result by showing that any EF1 allocation satisfies an 1/2-approximation guarantee and present an algorithm with a (1, 1/2) bi-criteria approximation guarantee. We finally show in a strategic setting that one can design a truthful mechanism with the proposed fair allocation.
3) Coalition Resistant Credit Score Functions.
In the third problem, we study manipulation in online discussion forums. We consider a specific but a common form of manipulation namely manipulation by coalition formation. We design a manipulation resistant credit scoring rule that assigns to each user a score such that forming a coalition is discouraged. In particular, we study the graph generated by the interactions on the platform and use community detection algorithms. We show that the community scores given by community detection algorithms that maximize modularity lead to a coalition resistant credit scoring rule. This in turn leads to sustainable discussion forums with honest participation from users, devoid of any coalitional manipulation.
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Lattimore, Finnian Rachel. "Learning how to act: making good decisions with machine learning." Phd thesis, 2017. http://hdl.handle.net/1885/144602.
Full textAbstract:
This thesis is about machine learning and statistical approaches
to decision making. How can we learn from data to anticipate the
consequence of, and optimally select, interventions or actions?
Problems such as deciding which medication to prescribe to
patients, who should be released on bail, and how much to charge
for insurance are ubiquitous, and have far reaching impacts on
our lives. There are two fundamental approaches to learning how
to act: reinforcement learning, in which an agent directly
intervenes in a system and learns from the outcome, and
observational causal inference, whereby we seek to infer the
outcome of an intervention from observing the system.
The goal of this thesis to connect and unify these key
approaches. I introduce causal bandit problems: a synthesis that
combines causal graphical models, which were developed for
observational causal inference, with multi-armed bandit problems,
which are a subset of reinforcement learning problems that are
simple enough to admit formal analysis. I show that knowledge of
the causal structure allows us to transfer information learned
about the outcome of one action to predict the outcome of an
alternate action, yielding a novel form of structure between
bandit arms that cannot be exploited by existing algorithms. I
propose an algorithm for causal bandit problems and prove bounds
on the simple regret demonstrating it is close to mini-max
optimal and better than algorithms that do not use the additional
causal information.
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Steadman, JA. "Banded iron formations, pyritic black shale, and gold deposits : a re-evaluation." Thesis, 2015. https://eprints.utas.edu.au/23246/1/Steadman_whole_thesis_ex_pub_mat.pdf.
Full textAbstract:
Banded iron formations (BIF) are predominantly Precambrian sedimentary rocks composed of alternating layers of iron-rich minerals (commonly hematite and magnetite, but also siderite, chlorite, and grunerite) and silica-rich minerals (e.g., quartz or chert) in which the Fe content of the entire rock is at least 15 wt. %. Although typically thought of as strictly Fe resources, such as in the worldclass Archean-Proterozoic Pilbara Craton of NW Australia, some BIF are associated with non-Fe ore resources, including (but not limited to) gold deposits in greenstone terranes. Due to fluctuations in ocean and atmospheric chemistry, BIF are commonly interbedded with pyritic black shales, which are regarded as waste material in Fe deposits but nonetheless are of great scientific interest (as are BIF) and potentially play a role in the creation of some gold resources (recent research has suggested that black shales are a source of Au and As in sediment-hosted gold deposits). The source of gold in these BIF, or more accurately, in BIF that host gold deposits, is a contentious issue in historical and modern economic geology. Over the past 40 years, debate in the economic geology community has revolved around whether the gold now in such deposits was an original part of the iron formation, or if it was introduced from an external, distant source. Less attention has been paid to the sources of As, Ag, and Te in these deposits, but as they commonly co-exist with gold in ore zones, determining their provenance is of relevance in assessing the origin of sediment-hosted and greenstone-hosted gold deposits.
In this thesis, black shales are investigated as the source of gold, arsenic, and tellurium at two BIF-hosted gold districts, Randalls (Australia) and Homestake (USA). The primary tools used in this investigation were petrography, textural analysis, whole-rock XRF, optical and scanning electron microscopy, and laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS). In particular, sulfides associated with the BIF-gold ores (e.g., pyrite, pyrrhotite, and arsenopyrite) and ‘background’ sulfides in non-BIF rocks a short distance from the ore zones were analyzed using laser ablation imaging and spot methods to determine their trace element contents and zonation (especially their Au, As, Ag, and Te concentrations). Special attention was paid to fine-grained, carbonaceous and sulfidic (meta) sedimentary rocks, or black shales, as these are widely acknowledged to be excellent source material for sediment-hosted gold, nickel, and copper deposits.
The Archean Randalls district (including Lucky Bay) is located in the southern Eastern Goldfields Superterrane, one of several crustal fragments that make up the Archean-Proterozoic Yilgarn Craton. The Yilgarn is one of the most gold-rich areas in the world, containing an estimated 9500 t (270 million ounces [Moz]) of Au. The Randalls district is located in the Belches Basin, one of several so-called ‘Late-Stage Basins’ in the Eastern Goldfields, and contains three BIF-hosted gold deposits (Cock-Eyed Bob, Maxwells, and Santa-Craze). Other styles of gold mineralization do occur in the area, such as the Daisy Milano deposit (quartz-vein lodes in altered basalts) and the Imperial-Majestic deposits (possible intrusion-related gold systems).
The >40 Moz (1300 t Au) Paleoproterozoic Homestake BIF-hosted deposit (the largest of its kind in the world) is located in the Black Hills dome of western South Dakota, which consists of an Archean- Proterozoic metasedimentary/metaigneous core flanked by Phanerozoic sediments; the current geologic architecture of the Black Hills was created during the 80–40 Ma Laramide orogeny, which formed the Rocky Mountains. Numerous felsic and alkalic intrusions were emplaced in all Precambrian and Phanerozoic units during this time, some of which are present in the Homestake mine area. These are commonly pyrite-bearing. At Randalls, the ore host BIF is enveloped by km-thick quartz- and feldspar-rich turbidites, with very little shale (and virtually no carbonaceous black shale). However, 10 km west of Cock-Eyed Bob is the Lucky Bay prospect, which contains abundant carbonaceous, fine-grained, and sulfidic (meta) black shale. This unit contains several types of pyrite, including pyrite nodules that are orders-of-magnitude more enriched in Au (0.1–2 ppm), As (500–10,000 ppm), Ag (1–100 ppm), and Te (0.5–50 ppm) than average crustal background levels. Other elements enriched in the Lucky Bay nodules are Co (500–1000 ppm), Ni (500–1000 ppm), Cu (100–500 ppm), Zn (50 ppm), Se (10–50 ppm), Mo (1–5 ppm), Sb (100–200 ppm), Hg (1000–2000 counts per second), Tl (0.5–10 ppm), Pb (500–1000 ppm), and Bi (20-50 ppm). Structural relationships observed in drill core and under the microscope suggest that these nodules are pre-metamorphic and pre-deformation, as evidenced by the ‘wrapping’ of bedding around the nodules. Pressure shadows containing quartz, mica, and a second generation of pyrite (plus sphalerite and chalcopyrite) also point to pre-deformational (likely syn-sedimentary or early diagenetic) growth.
Likewise, fine-grained (<0.5 mm diameter) anhedral pyrite and larger (up to 5 mm), partially recrystallized pyrite nodules in etamorphosed black shale at Homestake also have high amounts of Au (up to 0.5 ppm, average 0.3 ppm), As (up to 10,000 ppm), Ag (~10 ppm), Te (~10 ppm), and the other ore-associated elements noted above for pyrite nodules at Lucky Bay, though not quite at the same level as those nodules. This is likely due to the greater intensity of metamorphism (lower-middle amphibolite facies) experienced by lithologies at the Homestake deposit and surrounds, which recrystallized and partially converted the pyrite to pyrrhotite; pyrite at Lucky Bay (lower-middle greenschist facies) was spared this same fate. Furthermore, whole-rock analyses of the pyrite-bearing lithologies at Homestake show that the unit contains levels of V, Ag, Mo, Cu, and Zn on par with anomalous carbonaceous black shale (as published in the literature).
Lead isotopes of the pyrite nodules and the diagenetic pyrites from both localities appear to reinforce the claim that these pyrites did indeed form early in the history of the sedimentary units that host them. However, whereas Pb-Pb model ages of the Lucky Bay nodules are within error of the U-Pb depositional age, those from Homestake are hundreds of millions of years younger than the established intrusive, crystallization and depositional ages for all Proterozoic rock types in the Black Hills, suggesting that Pb loss and isotopic resetting had a major effect on minerals and rocks in and around Homestake. Futhermore, Pb isotope systematics of the eastern Yilgarn Craton are complex, such that two pyrites of otherwise different generations (i.e., sedimentary vs. ore-stage pyrite) can have Pb isotope compositions within error of each other. These aspects of the pyrite Pb isotope data from Lucky Bay and Homestake are here presented as caveats, not insurmountable obstacles, to the study and understanding of Pb isotope systematics in sulfides.
The sulfides within ore zones at both deposits do not contain the same high levels of trace elements, nor (with rare exceptions) do the amounts of the trace elements they have rival the levels of concentration seen in the various sedimentary pyrites outside the ore zone. At Randalls, pyrrhotite and arsenopyrite (the two major ore sulfides) are enriched in Co (up to 2000 ppm), Ni (up to 250 ppm), Se (up to 60 ppm), Mo (up to 50 ppm), Ag (up to 15 ppm), Sb (up to 200 ppm), and Te (up to 500 ppm). Certain elements, such as Mo and Te, are enriched only in arsenopyrite, while the rest are enriched at similar levels in both sulfides (furthermore, Te and Mo are more highly enriched in ore-stage arsenopyrite at Randalls than any other sulfide studied in this work). Arsenopyrite and pyrrhotite from Homestake (again the dominant ore zone sulfides) contain Co (50–1000 ppm), Ni (50–500 ppm), Se (100–200 ppm), Mo (10–100 ppm), Sb (50–500 ppm), Pb (1–100 ppm), and Bi (0.1–100 ppm). Many of the trace elements in the Randalls sulfides are strongly zoned, whereas the Homestake sulfide trace elements are more (but not completely) homogenized; as with the sedimentary pyrite above, this is interpreted to reflect higher metamorphic conditions attained at Homestake (lower-middle amphibolite facies) compared to Randalls (upper greenschist facies), which would lead to the expulsion of most trace impurities, or at least the erasure of original zonation.
This work demonstrates that certain trace elements, including those most commonly associated with sediment-hosted and greenstone-hosted gold deposits, were concentrated in upper-crustal siliciclastics during sedimentation or early diagenesis (that is, prior to later events that gave rise to sediment-hosted and greenstone-hosted gold deposits), and particularly in syn-sedimentary to early diagenetic pyrite. This research also has the potential to address metal source issues in some very large orogenic gold resources around the world: for example, an extension of the work completed here was conducted at the world-class, ~60 Moz dolerite-hosted Golden Mile Au district in Kalgoorlie, ~60 km NW of Lucky Bay and Randalls. Despite the overwhelming abundance of basalt, komatiite, and dolerite, three separate black shale layers are present in the district as interflow sediments between the mafic/ultramafic volcanic flows. All three units (Kapai Slate, Oroya Shale, and Black Flag Group shale) contain pyrite nodules with very similar internal and external textures to those at Lucky Bay. The likenesses between these nodules’ textures and the Lucky Bay nodules’ (including deformed bedding around the nodules) indicate that those at the Golden Mile are diagenetic, not hydrothermal.
LA-ICP-MS geochemical studies of the Golden Mile pyrite nodules reveals differences between the nodules from each formation, but also consistent characteristics. One of these, the Oroya Shale, contains diagenetic pyrite nodules with very similar textures to those from Lucky Bay, but the amount of Au and other trace elements contained in these nodules is significantly higher (e.g., up to 10 ppm Au dissolved in the pyrite structure). Given the abundance of this trace element-enriched pyrite in black shales (~5–10 vol. %), and the thickness and extent of this rock type at Lucky Bay (~7 km3), Homestake (~12 km3), and the Golden Mile (~3 km3), it is at least conceivable that a portion of the gold ore (plus As, Ag, and Te, in their various forms) now in the banded iron formations (and, by extension, the Golden Mile Dolerite) was sourced from the black shale units within the same succession (i.e., the stratigraphic footwall or hangingwall to the ore host).
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Trost, Travis Darren. "The fourth gospel as reaction to militant Jewish expectation of kingship, reflected in certain dead sea scrolls." Thesis, 2005. http://hdl.handle.net/10500/1985.
Full textAbstract:
The discovery of the Dead Sea Scrolls has provided an opportunity to reexamine the formation of the Gospel of John. This study will utilize Dead Sea finds coupled with other Second Temple literature to examine how the Gospel of John portrays Jesus as being a king. The approach of this study to use a narrative approach that builds on the Gospel of John as a finished text. The contribution of a source critical approach is not disparaged but the narrative approach will allow the Johannine community to be seen in the context of the immediate post-Second Temple era. The limited literacy of the probable first audience of this text suggests that a narrative approach will best be able to understand the background to the formation of the Gospel of John.
A central contention of this study is that the Gospel of John was composed after the Jewish Revolt and after the Synoptics. Thus it deserves the appellation of the Fourth Gospel and is called such in this study. The Fourth Gospel was composed at a time when Roman interest in anything connected to Judaism was sure to attract special interest. Thus the portrayal of Jesus as the Davidic Messiah needed to be handled carefully. The imagery of the new David found in 4Q504 compared with the imagery of Jesus being the Good Shepherd becomes an important part of the argument of this study on whether this Gospel portrays Jesus as being the Davidic Messiah. Jesus as the Good Shepherd showed Jews that Jesus is the Davidic Messiah without overtly offending Roman sensibilities. Furthermore evidence from Christian and Jewish sources indicates that an interest in a Third Temple was still stirring between the Jewish and Bar-Kochba Revolts. The Fourth Gospel shows Jesus as the Davidic Messiah who replaces the Temple because the Good Shepherd was the perfect sacrifice.<br>New Testament<br>D. Th. (New Testament)
Books on the topic "Good Bandit"
2
Varley, James F. The legend of Joaquín Murrieta: California's Gold Rush bandit. Big Lost River Press, 1995.
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3
Peralta, Joaquin. Bandits!: A dangerous adventure on gold rush trails. BalonaBooks, 2008.
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4
Gwaltney, Don. The bandit Joaquín: An orphaned Mexican's search for revenge in the California gold rush. Apple Core Press, 1997.
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Sutthikunsombat, Suthatsanā. Rāingān kānwičhai rư̄ang thammāphibān khō̜ng kō̜ngthun mūbān læ chumchon mư̄ang tām khwāmkhithen khō̜ng bandit kō̜ngthun nai Čhangwat ʻUdō̜n Thānī, Nō̜ng Khāi læ Nō̜ng Būa Lamphū =: Good governance of village and urban revolving fund in the opinions of gra[d]uate diploma in Udonthani Nong Khai and Nongbualamphu Provinces. Sathāban Rātchaphat ʻUdō̜n Thānī, 2002.
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Sutthikunsombat, Suthatsanā. Rāingān kānwičhai rư̄ang thammāphibān khō̜ng kō̜ngthun mūbān læ chumchon mư̄ang tām khwāmkhithen khō̜ng bandit kō̜ngthun nai Čhangwat ʻUdō̜n Thānī, Nō̜ng Khāi læ Nō̜ng Būa Lamphū =: Good governance of village and urban revolving fund in the opinions of gra[d]uate diploma in Udonthani Nong Khai and Nongbualamphu Provinces. Sathāban Rātchaphat ʻUdō̜n Thānī, 2002.
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Hayward, Anthony. Gold: The making of Band of gold and the sequel Gold. Chameleon in association with Granada Television, 1997.
Find full textBook chapters on the topic "Good Bandit"
1
Kummer, Ulrike. "„Gold von Mitternacht“ – Zu Leben und Werk des Arztpietisten Johann Philipp Maul (1662–1727)." In Pietismus und Neuzeit Band 40 - 2014. Vandenhoeck & Ruprecht, 2014. http://dx.doi.org/10.13109/9783666559129.134.
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Huston, David L., Robert B. Trumbull, Georges Beaudoin, and Trevor Ireland. "Light Stable Isotopes (H, B, C, O and S) in Ore Studies—Methods, Theory, Applications and Uncertainties." In Isotopes in Economic Geology, Metallogenesis and Exploration. Springer International Publishing, 2023. http://dx.doi.org/10.1007/978-3-031-27897-6_8.
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AbstractVariations in the abundances of light stable isotopes, particularly those of hydrogen, boron, carbon, oxygen and sulfur, were essential in developing mineralization models. The data provide constraints on sources of hydrothermal fluids, carbon, boron and sulfur, track interaction of these fluids with the rocks at both the deposit and district scales, and establish processes of ore deposition. In providing such constraints, isotopic data have been integral in developing genetic models for porphyry-epithermal, volcanic-hosted massive sulfide, orogenic gold, sediment-hosted base metal and banded-iron formation-hosted iron ore systems, as discussed here and in other chapters in this book. After providing conventions, definitions and standards used to present stable isotope data, this chapter summarizes analytical methods, both bulk and in situ, discusses processes that fractionate stable isotopes, documents the isotopic characteristics of major fluid and rock reservoirs, and then shows how stable isotope data have been used to better understand ore-forming processes and to provide vectors to ore. Analytical procedures, initially developed in the 1940s for carbon–oxygen analysis of bulk samples of carbonate minerals, have developed so that, for most stable isotopic systems, spots as small as a few tens of μm are routinely analyzed. This precision provides the paragenetic and spatial resolution necessary to answer previously unresolvable genetic questions (and create new questions). Stable isotope fractionation reflects geological and geochemical processes important in ore formation, including: (1) phase changes such as boiling, (2) water–rock interaction, (3) cooling, (4) fluid mixing, (5) devolatilization, and (6) redox reactions, including SO2 disproportionation caused by the cooling of magmatic-hydrothermal fluids and photolytic dissociation in the atmosphere. These processes commonly produce gradients in isotopic data, both in time and in space. These gradients, commonly mappable in space, provide not only evidence of process but also exploration vectors. Stable isotope data can be used to estimate the conditions of alteration or mineralization when data for coexisting minerals are available. These estimates use experimentally- or theoretically-determined fractionation equations to estimate temperatures of mineral formation. If the temperature is known from isotopic or other data (e.g., fluid inclusion data or chemical geothermometers), the isotopic composition of the hydrothermal fluid components can be estimated. If fluid inclusion homogenization and compositional data exist, the pressure and depth of mineralization can be estimated. One of the most common uses of stable isotope data has been to determine, or more correctly delimit, fluid and sulfur sources. Estimates of the isotopic compositions of hydrothermal fluids, in most cases, do not define unequivocal sources, but, rather, eliminate sources. As an example, the field of magmatic fluids largely overlap that of metamorphic fluids in δ18O-δD space, but are significantly different to the fields of meteoric waters and seawater. As such, a meteoric or seawater origin for a fluid source may be resolvable, but a magmatic source cannot be resolved from a metamorphic source. Similarly, although δ34S ~ 0‰ is consistent with a magmatic-hydrothermal sulfur source, the signature can also be produced by leaching of an igneous source. Recent analytical and conceptual advances have enabled gathering of new types of isotopic data and application of these data to resolve new problems in mineral deposit genesis and geosciences in general. Recent developments such as rapid isotopic analysis of geological materials or clumped isotopes will continue to increase the utility of stable isotope data in mineral deposit genesis and metallogeny, and, importantly, for mineral exploration.
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Dugmore, Dan. "BLACKA AND THE BANDIT." In A Perfectly Good Guitar. University of Texas Press, 2017. http://dx.doi.org/10.7560/312575-010.
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"Juan Nepomuceno Cortina: Proclamation to the Mexicans of Texas, November 1859." In Schlager Anthology of Hispanic America. Schlager Group Inc., 2023. https://doi.org/10.3735/9781935306856.book-part-045.
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In the years following the Treaty of Guadalupe Hidalgo in 1848, white settlers migrated into the American Southwest, where disputes over land and wealth led to conflict between the two groups. Juan Cortina, a wealthy landowner in Brownsville, Texas, led a group of men in armed conflict against Texas law enforcement. As Cortina and his followers confronted local law enforcement officers who had murdered and taken the land of various Mexicans, Cortina issued two proclamations to explain and justify his reasons for violence. In his November proclamation, Cortina explains his motives in taking up arms against the Anglos. Cortina points out that Mexicans have been denied the promises of American citizenship given to them by the Treaty of Guadalupe Hidalgo, and he describes the characteristics of the Mexican race that provide the strength for them to overcome their oppressors. Corina proudly takes the title of “bandit” and promises to fight for the good of the Mexican people until they are treated with respect and given equal treatment under the law.
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"P. I. Iurkevich’s Gaidamak Garkusha, Wherein the Little Russian Bandit Takes His Final Bow (But Is It Good for the Jews?)." In Cossacks in Jamaica, Ukraine at the Antipodes. Academic Studies Press, 2020. http://dx.doi.org/10.1515/9781644693025-012.
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Koropeckyj, Roman. "P. I. Iurkevich’s Gaidamak Garkusha, Wherein the Little Russian Bandit Takes His Final Bow (But Is It Good for the Jews?)." In Cossacks in Jamaica, Ukraine at the Antipodes. Academic Studies Press, 2020. http://dx.doi.org/10.2307/j.ctv1zjg9jq.15.
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Kearney, L., and V. J. Buckle. "The application of fluorescence in situ hybridization to chromosome analysis." In Human Cytogenetics: constitutional analysis. Oxford University PressOxford, 2001. http://dx.doi.org/10.1093/oso/9780199638406.003.0006.
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Abstract For over two decades banding has remained the ‘gold standard’ of cytogenetic analysis, providing the first genome-wide screen for abnormalities. However, conventional cytogenetic banding techniques are limited to the detection of rearrangements involving more than 2 Mb of DNA. In addition, the identification of de nova unbalanced chromosome rearrangements provides a particular challenge for chromosome banding to decipher. In recent years a number of techniques based around FISH have evolved, all of which complement the conventional banding approaches and which have steadily increased the accuracy of cytogenetic diagnosis.
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Terpstra, Taco. "King’s Men and the Stationary Bandit." In Trade in the Ancient Mediterranean. Princeton University Press, 2019. http://dx.doi.org/10.23943/princeton/9780691172088.003.0003.
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This chapter examines mid-third-century BCE Syria-Palestine, an area ruled by the Ptolemies at the time. As in all Hellenistic states, the power structure of the Ptolemaic kingdom was strongly personalized. A small number of state actors surrounding the king were allowed access to agricultural surplus, making them influential men politically and economically. Moreover, the process by which the ruling elite negotiated power through conspicuous consumption, diplomatic tokens, and gift-giving drove the wheels of an expanding economy of long-distance trade in both luxury goods and agricultural staples. The chapter then considers the activities of a certain Zenon, who was an agent of the Ptolemaic finance minister Apollonios. By tracing the activities of these men, one can analyze how—as a public official—Apollonios managed the Ptolemaic overseas territory of Syria-Palestine. Ultimately, the Ptolemaic state that Apollonios served provided public goods, including a banking system and a public-order apparatus.
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Akeson, Ellen C., and Muriel T. Davisson. "Analysing mouse chromosomal rearrangements with G-banded chromosomes." In Mouse Genetics and Transgenics, edited by Ian J. Jackson. Oxford University PressOxford, 1999. http://dx.doi.org/10.1093/oso/9780199637096.003.0006.
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Abstract This section describes the preparation of metaphase chromosomes from mouse peripheral blood lymphocytes for chromosomal typing of living mice. Included is a list of mouse strains and their relative response to phyto-haemagglutinin (PHA), a list of the requirements necessary for the production of well-spread metaphase chromosomes with good morphology for banding, a Giemsa banding (G-band) method for these chromosomes, and their classification into a karyotype. The identification of mouse chromosomes is presented with a detailed process for determining aberrant chromosomes and describing the common pitfalls of misclassification. A precise description of the characteristic banding patterns (landmarks) at different stages of chromo some condensation is presented elsewhere (1). The cell-harvesting part of the procedure also can be used to prepare mitotic chromosomes directly from fetal liver or bone marrow.
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Barrenechea, Antonio. "Black God, White Devil (1964)." In Routledge Encyclopedia of Modernism. Routledge, 2018. http://dx.doi.org/10.4324/9781135000356-rem1934-1.
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Black God, White Devil is a 1964 film directed by Brazilian auteur Glauber Rocha. Shot on location in the Brazilian sertão, it launched the cinema novo movement and embodied the aspirations of a new political cinema, as outlined in Rocha’s 1965 essay ‘An Esthetic of Hunger.’ Black God, White Devil forms a trilogy with Terra em Transe (1967) and Antonio das Mortes (1969). It revolutionized the national film industry by merging the European avant-garde cinema (Soviet montage, Italian Neorealism, French New Wave) and Brazilian folk traditions. In the film, a couple fleeing from poverty and law enforcement explore two ways of feeding their physical and spiritual hunger. Both of these prove unfulfilling. The first is by joining the messianic cult of a beato or saint (the black God). The second is by following a cangaceiro, an archetypal bandit from the sertão (the white Devil). Black God, White Devil shifted attention away from the dominant chanchada musical comedy in favour of an epic drama set on Brazil’s northeastern backlands. The highly symbolic plot fuses poetically with a soundtrack punctuated by Heitor Villa-Lobos’s Bachianas Brasileiras. Stylized performances, handheld camera shots, elliptical editing, and nonsynchronous sound disrupt traditional viewing habits, while also culminating in the dialectical fulfilment of a filmic refrain: ‘The sertão will become sea, and the sea sertão.’
Conference papers on the topic "Good Bandit"
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Eltaieb, Rania A., Sophie LaRochelle, and Leslie A. Rusch. "Performance Trade-offs Spanning O-C-L-bands in Antiresonant Fiber Designs." In Specialty Optical Fibers. Optica Publishing Group, 2024. http://dx.doi.org/10.1364/sof.2024.sow2f.2.
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We examine antiresonant nodeless fiber (ANF) geometries with good C-band compromises between single-mode operation and loss. We identify one geometry offering good trade-offs throughout the antiresonance window, particularly in the telecommunications O-band and L-band.
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Weltschev, Margit, Anka Kohl, Manuela Haufe, and Jan Werner. "Use of Fourier Transform Infrared Spectroscopy to Characterize Nitric Acid Oxidation of Polyethylene Grades." In CORROSION 2013. NACE International, 2013. https://doi.org/10.5006/c2013-02070.
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Abstract Resistance to oxidative degradation by nitric acid has been selected for a comparison of polyethylene grades in a European standard on suitability proof for alternative plastic resins used for packagings and intermediate bulk containers (IBCs) for the transport of dangerous goods. Measurements of the infrared (IR) absorption spectra of microtome slices cut from the walls of jerricans, which were pre-stored with 55% nitric acid for 21 and 42 days at 40°C, showed changes in the structure of the polyethylene. The penetration depths of 55% nitric acid into the polyethylene grades are, in principle, suitable for evaluating the resistance to oxidative degradation of polyethylene grades after pre-storage of the packagings for 21 days. After this period the packaging wall is not fully penetrated. The intensities of the IR bands at 1565 cm-1 (-NO2), 1630 cm-1 (-C=C) and 1654 cm-1 (-O-NO2) increased with the treatment time with 55% nitric acid as a result of oxidative damage by the nitric acid. The high increase in absorbance of the -C=C band in the region 1630 - 1690 cm-1 is attributable to paraffinic chain cracks. The absorbance of the -O-NO2 band, formed as result of the nitration process was still low at a test temperature of 40°C.
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Varsha and Gautam Das. "Tunable passively Q-Switched and Mode-Locked fiber laser at 1.9 µm region using a mixture of Gold nanorods and Polyvinyl Alcohol as a Saturable Absorber." In Latin America Optics and Photonics Conference. Optica Publishing Group, 2024. https://doi.org/10.1364/laop.2024.tu2a.5.
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Heckman, Stephen M. "Stop Hiring Bad Employees!" In Paint and Coatings Expo (PACE) 2007. SSPC, 2007. https://doi.org/10.5006/s2007-00039.
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Abstract A shrinking pool of quality employee candidates has made it increasingly difficult to hire good people for your business. A band of inferior hopefuls stand outside your door, hoping to gain entry and wreak havoc in your business – you represent the only barrier that keeps them from coming through. Being able to see through their smoke and mirrors will improve the odds of hiring someone that will represent you and your company well.
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Davis, Gerald O., and Michael A. Streicher. "Initiation of Chloride Crevice Corrosion on Stainless Alloys." In CORROSION 1985. NACE International, 1985. https://doi.org/10.5006/c1985-85205.
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Abstract The reproducibility and applicability of two accelerated laboratory tests and three different crevice devices were evaluated for measuring the resistance of three stainless alloys to initiation of chloride crevice corrosion. A ferric chloride immersion test and an electrochemical test in synthetic sea water with potentiostatic control of the applied potential were evaluated. For both tests, temperature, applied in progressively increasing steps, was used as the criterion for ranking the resistance to initiation of attack. The findings (critical crevice corrosion temperatures, CCCT) were correlated with results on the same three stainless alloys obtained in long-term tests by others in natural sea water at ambient temperatures. The three types of crevice-forming devices were: 1) rubber band-Teflon, 2) serrated washers (Delrin), and 3) ceramic (alumina) washers without serrations. The alloys selected ranged from relatively low (Fe-21Cr-25Ni-4.4Mo) to medium (Fe-26Cr-5.6Ni-3.2Mo) to high (Fe-29Cr-4Mo) resistance to chloride corrosion. Ranking for initiation of crevice corrosion of the alloys by CCCT values in both accelerated laboratory tests was in good agreement with that obtained for initiation in long-term exposure in natural sea water. The reproducibility of the data for each test was good. The CCCT values in the controlled potential electrochemical test in synthetic sea water were independent of the type of crevice device used. However, in the slower simple immersion test in ferric chloride there were significant differences in CCCT values as a function of the crevice device. In the ferric chloride test, CCCT values increased in the following order: Delrin serrated washer, rubber band-Teflon, and alumina washer.
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Saha, Peash Ranjan, Salimur Choudhury, and Kai Salomaa. "Altruistic Bandit Learning For One-to-Many Matching Markets." In GoodIT '24: International Conference on Information Technology for Social Good. ACM, 2024. http://dx.doi.org/10.1145/3677525.3678661.
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Zheng, Jiongzhi, Kun He, Jianrong Zhou, Yan Jin, Chu-Min Li, and Felip Manyà. "BandMaxSAT: A Local Search MaxSAT Solver with Multi-armed Bandit." In Thirty-First International Joint Conference on Artificial Intelligence {IJCAI-22}. International Joint Conferences on Artificial Intelligence Organization, 2022. http://dx.doi.org/10.24963/ijcai.2022/264.
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We address Partial MaxSAT (PMS) and Weighted PMS (WPMS), two practical generalizations of the MaxSAT problem, and propose a local search algorithm called BandMaxSAT, that applies a multi-armed bandit to guide the search direction, for these problems. The bandit in our method is associated with all the soft clauses in the input (W)PMS instance. Each arm corresponds to a soft clause. The bandit model can help BandMaxSAT to select a good direction to escape from local optima by selecting a soft clause to be satisfied in the current step, that is, selecting an arm to be pulled. We further propose an initialization method for (W)PMS that prioritizes both unit and binary clauses when producing the initial solutions. Extensive experiments demonstrate that BandMaxSAT significantly outperforms the state-of-the-art (W)PMS local search algorithm SATLike3.0. Specifically, the number of instances in which BandMaxSAT obtains better results is about twice that obtained by SATLike3.0. We further combine BandMaxSAT with the complete solver TT-Open-WBO-Inc. The resulting solver BandMaxSAT-c also outperforms some of the best state-of-the-art complete (W)PMS solvers, including SATLike-c, Loandra and TT-Open-WBO-Inc.
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Bouneffouf, Djallel, Srinivasan Parthasarathy, Horst Samulowitz, and Martin Wistuba. "Optimal Exploitation of Clustering and History Information in Multi-armed Bandit." In Twenty-Eighth International Joint Conference on Artificial Intelligence {IJCAI-19}. International Joint Conferences on Artificial Intelligence Organization, 2019. http://dx.doi.org/10.24963/ijcai.2019/279.
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We consider the stochastic multi-armed bandit problem and the contextual bandit problem with historical observations and pre-clustered arms. The historical observations can contain any number of instances for each arm, and the pre-clustering information is a fixed clustering of arms provided as part of the input. We develop a variety of algorithms which incorporate this offline information effectively during the online exploration phase and derive their regret bounds. In particular, we develop the META algorithm which effectively hedges between two other algorithms: one which uses both historical observations and clustering, and another which uses only the historical observations. The former outperforms the latter when the clustering quality is good, and vice-versa. Extensive experiments on synthetic and real world datasets on Warafin drug dosage and web server selectionfor latency minimization validate our theoretical insights and demonstrate that META is a robust strategy for optimally exploiting the pre-clustering information.
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Mao, Weichao, Zhenzhe Zheng, Fan Wu, and Guihai Chen. "Online Pricing for Revenue Maximization with Unknown Time Discounting Valuations." In Twenty-Seventh International Joint Conference on Artificial Intelligence {IJCAI-18}. International Joint Conferences on Artificial Intelligence Organization, 2018. http://dx.doi.org/10.24963/ijcai.2018/61.
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Online pricing mechanisms have been widely applied to resource allocation in multi-agent systems. However, most of the existing online pricing mechanisms assume buyers have fixed valuations over the time horizon, which cannot capture the dynamic nature of valuation in emerging applications. In this paper, we study the problem of revenue maximization in online auctions with unknown time discounting valuations, and model it as non-stationary multi-armed bandit optimization. We design an online pricing mechanism, namely Biased-UCB, based on unique features of the discounting valuations. We use competitive analysis to theoretically evaluate the performance guarantee of our pricing mechanism, and derive the competitive ratio. Numerical results show that our design achieves good performance in terms of revenue maximization on a real-world bidding dataset.
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ElSayed, Karim A., Ilias Bilionis, and Jitesh H. Panchal. "Evaluating Heuristics in Engineering Design: A Reinforcement Learning Approach." In ASME 2021 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/detc2021-70425.
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Abstract Heuristics are essential for addressing the complexities of engineering design processes. The goodness of heuristics is context-dependent. Appropriately tailored heuristics can enable designers to find good solutions efficiently, and inappropriate heuristics can result in cognitive biases and inferior design outcomes. While there have been several efforts at understanding which heuristics are used by designers, there is a lack of normative understanding about when different heuristics are suitable. Towards addressing this gap, this paper presents a reinforcement learning-based approach to evaluate the goodness of heuristics for three sub-problems commonly faced by designers: (1) learning the map between the design space and the performance space, (2) acquiring sequential information, and (3) stopping the information acquisition process. Using a multi-armed bandit formulation and simulation studies, we learn the suitable heuristics for these individual sub-problems under different resource constraints and problem complexities. Additionally, we learn the optimal heuristics for the combined problem (i.e., the one composing all three sub-problems), and we compare them to ones learned at the sub-problem level. The results of our simulation study indicate that the proposed reinforcement learning-based approach can be effective for determining the quality of heuristics for different problems, and how the effectiveness of the heuristics changes as a function of the designer’s preference (e.g., performance versus cost), the complexity of the problem, and the resources available.
Reports on the topic "Good Bandit"
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Tóth, Z., B. Dubé, B. Lafrance, V. Bécu, K. Lauzière, and P. Mercier-Langevin. Whole-rock lithogeochemistry of the banded iron-formation-hosted gold mineralization in the Geraldton area, northwestern Ontario. Natural Resources Canada/CMSS/Information Management, 2023. http://dx.doi.org/10.4095/331919.
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This report releases 235 runs of whole-rock geochemical and assay results of 235 samples/subsamples from the Archean banded iron formation-hosted gold mineralization in the Geraldton area, eastern Wabigoon subprovince, northwestern Ontario. The samples were collected during the 2012, 2013, 2014 and 2016 field seasons as part of a PhD study by the senior author (T�th, 2018) at Laurentian University in Sudbury. Geochemical analyses were paid in part by the GSC for the 2012, 2013 samples, while the 2014 and 2016 samples were graciously paid by the second author, Bruno Lafrance and Greenstone Gold Mines, respectively. Research on gold mineralization hosted in banded iron formation BIF was conducted under the Lode Gold project of TGI4. The geochemical data is presented in a format easily importable in a geographic information system (GIS). Samples were collected from drill core and outcrops to document host units, the alteration halo, and the mineralized zones. Preliminary interpretations about the auriferous mineralization and its geological setting are presented in Lafrance et al. (2012) and in T�th et al. (2013a, 2013b, 2014, 2015a, 2015b). The final interpretation of the geological setting of the gold mineralization was published in T�th and others (2022, 2023). Sample information and geochemical results are presented in Appendices 1 and 2 (worksheet "Results"), respectively. The results worksheet combines 5 reports produced between 2012 and 2016.
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Janvier, V., S. Castonguay, P. Mercier-Langevin, et al. Geology of the banded iron formation-hosted Meadowbank gold deposit, Churchill Province, Nunavut. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2015. http://dx.doi.org/10.4095/296646.
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Gourcerol, B., P. C. Thurston, D. J. Kontak, O. Côté-Mantha, and J. Biczok. Depositional setting of Algoma-type banded iron formation from the Meadowbank, Meliadine, and Musselwhite gold deposits. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2015. http://dx.doi.org/10.4095/296629.
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Valette, M., S. De Souza, P. Mercier-Langevin, et al. Geological setting of the 5.2 Moz Au Amaruq banded iron formation-hosted gold deposit, Churchill Province, Nunavut. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2019. http://dx.doi.org/10.4095/313643.
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Tòth, Z., B. Lafrance, B. Dubé, P. Mercier-Langevin, and V. McNicoll. Geological setting of banded iron formation-hosted gold mineralization in the Geraldton area, Northern Ontario: preliminary results. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2013. http://dx.doi.org/10.4095/292558.
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Tóth, Z., B. Lafrance, B. Dubé, V. J. McNicoll, P. Mercier-Langevin, and R. A. Creaser. Banded iron formation-hosted gold mineralization in the Geraldton area, northwestern Ontario: structural setting, mineralogical characteristics and geochronology. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2015. http://dx.doi.org/10.4095/296631.
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Tóth, Z., B. Lafrance, B. Dubé, P. Mercier-Langevin, and V. J. McNicoll. Structural setting, mineralogical characteristics and geochemical footprints of banded-iron-formation-hosted gold mineralization in the Geraldton area, Ontario. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2015. http://dx.doi.org/10.4095/295526.
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Nunes, João, and Sérgio Lagoa. Lessons from the collapse of two banks in Portugal: Implications for banking management and regulation. DINÂMIA'CET-Iscte, 2023. http://dx.doi.org/10.15847/dinamiacet-iul.wp.2023.04.
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It is almost 10 years since one of Portugal’s five largest banks, BES, was subject to a bank resolution measure. In 2015, another large bank, BANIF, followed the same path. Now that some time has passed and the full consequences of the resolutions materialised, it is time to reflect on the causes of the crises at these two banks and to draw lessons for the future. In addition to looking into the relevant literature, official company reports, parliamentary inquiries, newspapers and other public information, we examine whether key financial ratios could have raised a red flag. We conclude that the collapses were explained by a mixture of macrostructural causes and above all bank-specific factors. The two cases are good illustrations of the negative effects of financialisation in the Portuguese economy. The key profitability and risk indicators provided some timely indications of the problems facing the two banks.
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Valette, M., S. De Souza, P. Mercier-Langevin, et al. Lithological and tectonic controls on banded iron formation-associated gold at the Amaruq deposit, Churchill Province, Nunavut, and implications for exploration. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2020. http://dx.doi.org/10.4095/326042.
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Gourcerol, B., P. C. Thurston, D. J. Kontak, O. Côté-Mantha, and J. Biczok. Distinguishing primary and mineralization-related signatures of chert from the banded iron-formation-hosted gold deposits at Musselwhite, Ontario and Meadowbank, Nunavut. Natural Resources Canada/ESS/Scientific and Technical Publishing Services, 2015. http://dx.doi.org/10.4095/295531.
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