The Market Fraction Hypothesis under different GP algorithms

In a previous work, inspired by observations made in many agent-based financial models, we formulated and presented the Market Fraction Hypothesis, which basically predicts a short duration for any dominant type of agents, but then a uniform distribution over all types in the long run. We then proposed a two-step approach, a rule-inference step and a rule-clustering step, to testing this hypothesis. We employed genetic programming as the rule inference engine, and applied self-organizing maps to cluster the inferred rules. We then ran tests for 10 international markets and provided a general examination of the plausibility of the hypothesis. However, because of the fact that the tests took place under a GP system, it could be argued that these results are dependent on the nature of the GP algorithm. This chapter thus serves as an extension to our previous work. We test the Market Fraction Hypothesis under two new different GP algorithms, in order to prove that the previous results are rigorous and are not sensitive to the choice of GP. We thus test again the hypothesis under the same 10 empirical datasets that were used in our previous experiments. Our work shows that certain parts of the hypothesis are indeed sensitive on the algorithm. Nevertheless, this sensitivity does not apply to all aspects of our tests. This therefore allows us to conclude that our previously derived results are rigorous and can thus be generalized

CES-509 Market Microstructure: Can Dinosaurs Return? A Self-Organizing Map Approach under an Evolutionary Framework

This paper extends a previous model where we examined the markets' microstructure dynamics by using Genetic Programming as a trading rule inference engine, and Self Organizing Maps as a cluster- ing machine for those rules. However, an assumption we made in that model was that clusters, and thus trading strategy types, had to remain the same over time. This assumption could be considered unrealistic, but it was necessary for the purposes of our tests. For this reason, in this paper we extend this model by relaxing this assumption. Hence our framework does not lie on pre-speci?ed types, nor do these types remain the same throughout time. This allows us to investigate the dynamics of market behavior and more speci?cally whether successful strategies from the past can be successfully applied to the future. In the past, we investigated this phenomenon by using a simple ?tness test. Neverthe- less, a drawback of that approach was that because of its simplicity, it could only o?er limited understanding of the complex dynamics of mar- ket behavior. With the extended model we can thus have a more realistic view of the markets and hence draw safer conclusions about their behav- ior. Empirical results show that market behavior is non-stationary, and thus agents' strategies need to continuously co-evolve with the market, in order to remain eff?ective

CES-511 The Market Fraction Hypothesis under different GP algorithms

In a previous work, inspired by observations made in many agent-based financial models, we formulated and presented the Market Fraction Hypothesis, which basically predicts a short duration for any dominant type of agents, but then a uniform distribution over all types in the long run. We then proposed a two-step approach, a rule-inference step and a rule-clustering step, to testing this hypothesis. We employed genetic programming as the rule in- ference engine, and applied self-organizing maps to cluster the inferred rules. We then ran tests for 10 international markets and provided a general examination of the plausibility of the hypothesis. However, because of the fact that the tests took place under a GP system, it could be argued that these results are dependent on the nature of the GP algorithm. This chapter thus serves as an extension to our previous work. We test the Market Fraction Hypothesis under two new different GP algorithms, in order to prove that the previous results are rigorous and are not sensitive to the choice of GP. We thus test again the hypothesis under the same 10 empirical datasets that were used in our previous experiments. Our work shows that certain parts of the hypothesis are indeed sensitive on the algorithm. Nevertheless, this sensitivity does not apply to all aspects of our tests. This therefore allows us to conclude that our previously derived results are rigorous and can thus be generalized

The exceptionally high diversity of small carnivorans from the Late Miocene hominid locality of Hammerschmiede (Bavaria, Germany)

The present study deals with new material of carnivorans (Mustelidae, Mephitidae, Ailuridae, Potamotheriinae and Viverridae) from the basal Tortonian (Late Miocene, late Astaracian) hominid-bearing locality of Hammerschmiede (Bavaria, Germany). The small carnivoran fauna includes 20 species belonging to nine different subfamilies (Guloninae, Lutrinae, Mellivorinae, Potamotheriinae, Leptarctinae, Mephitinae, Simocyoninae, Genettinae and Viverrinae). The identified forms include: “Martes” sansaniensis, “Martes” cf. munki, “Martes” sp., Circamustela hartmanni n. sp., Laphyctis mustelinus, Guloninae indet., Eomellivora moralesi, Vishnuonyx neptuni, Paralutra jaegeri, Lartetictis cf. dubia, Trocharion albanense, Palaeomeles pachecoi, Proputorius sansaniensis, Proputorius pusillus, Alopecocyon goeriachensis, Simocyoninae indet., Potamotherium sp., Semigenetta sansaniensis, Semigenetta grandis and Viverrictis modica. The new species Circamustela hartmanni n. sp. is differentiated from the other members of the genus by its small size and the morphology of its dental cusps in the upper and lower carnassials. This is one of the highest reported taxonomic diversities for fossil small carnivorans in the Miocene of Europe, including also first and last occurrences for several genera and species. Additionally, the assemblage comprises some rare taxa such as Palaeomeles pachecoi and Eomellivora moralesi. An ecomorphological comparison of the discovered taxa reveals possible cases of competition and niche partitioning. © 2022 Kargopoulos et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Investment Opportunities Forecasting: Extending the Grammar of a GP-based Tool

In this paper we present a new version of a GP financial forecasting tool, called EDDIE 8. The novelty of this version is that it allows the GP to search in the space of indicators, instead of using pre-specified ones. We compare EDDIE 8 with its predecessor, EDDIE 7, and find that new and improved solutions can be found. Analysis also shows that, on average, EDDIE 8's best tree performs better than the one of EDDIE 7. The above allows us to characterize EDDIE 8 as a valuable forecasting tool

Applications of Genetic Programming to Finance and Economics: Past, Present, Future

While the origins of Genetic Programming (GP) stretch back over fifty years, the field of GP was invigorated by John Koza’s popularisation of the methodology in the 1990s. A particular feature of the GP literature since then has been a strong interest in the application of GP to real-world problem domains. One application domain which has attracted significant attention is that of finance and economics, with several hundred papers from this subfield being listed in the Genetic Programming Bibliography. In this article we outline why finance and economics has been a popular application area for GP and briefly indicate the wide span of this work. However, despite this research effort there is relatively scant evidence of the usage of GP by the mainstream finance community in academia or industry. We speculate why this may be the case, describe what is needed to make this research more relevant from a finance perspective, and suggest some future directions for the application of GP in finance and economics

Guided Fast Local Search for Speeding Up a Financial Forecasting Algorithm

Guided Local Search is a powerful meta-heuristic algorithm that has been applied to a successful Genetic Programming Financial Forecasting tool called EDDIE. Although previous research has shown that it has significantly improved the performance of EDDIE, it also increased its computational cost to a high extent. This paper presents an attempt to deal with this issue by combining Guided Local Search with Fast Local Search, an algorithm that has shown in the past to be able to significantly reduce the computational cost of Guided Local Search. Results show that EDDIE's computational cost has been reduced by an impressive 77%, while at the same time there is no cost to the predictive performance of the algorithm

Politisk ledelse i et kvinneperspektiv : en studie av kvinneandelen i politiske lederposisjoner i Alta kommune

Masteroppgaven "Politisk ledelse i et kvinneperspektiv" er en studie av kvinneandelen i politiske lederposisjoner i Alta kommune for perioden 1999-2007. I oppgaven rettes fokuset mot hva som kan forklare den lave kvinneandelen i sentrale politiske lederposisjoner, som omfatter tre kommunevalgperioder. Jeg har valgt å fokusere på både interne og eksterne forhold. Interne forhold er formelle forhold tilknyttet rekruttering og valg, uformelle forhold knyttet til motivasjon, kultur og holdninger på den ene siden og politisk maktkamp på den andre. Når det gjelder eksterne forhold har jeg valgt å fokusere på medias makt og kvinneprofilering. Jeg har benyttet både kvantitativ og kvalitativ metode ved innsamling av data, det vil si både spørreskjema og intervju. Det innsamlede materialet er analysert i forhold til relevant teori og forskning. Undersøkelsen viser at både interne og eksterne forhold påvirker kjønnsbalansen i politiske lederposisjoner på en negativ måte. Hovedforklaringen og den utløsende faktoren synes å være velgernes endring av valglistene, som fører til at kvinneandelen er redusert fra 50 % på valglistene til mellom 32 % og 35 % de tre siste kommunestyreperiodene. Virkningen er som en dominoeffekt. Dersom det skal oppnås kjønnsbalanse i sentrale politisk lederverv må valg av politisk ledelse skje uavhengig av valgresultatet. Det bør iverksettes målrettede tiltak som foreslått i kapittel 5 og det er behov for videre forskning innenfor området. Det bør i tillegg gjennomføres en velgerundersøkelse der fokus rettes mot kjønnsbalanse i kommunestyret og i den politiske ledelsen

Supplementary Material for: Internal carotid artery dissection presenting with transient or subclinical Horner syndrome

Introduction The most frequently encountered symptoms in internal carotid artery dissection (ICAD) are head or neck pain and cerebral ischemia. Ocular symptoms or signs have been reported as the presenting feature in up to 50% of patients, with (painful) Horner syndrome being the most frequently associated. Horner syndrome is part of the classic triad that depicts the characteristic presentation of ICAD, and that consists of pain in the ipsilateral neck, head and orbital regions, (partial) Horner syndrome, and cerebral or retinal ischemia. All patients presenting with painful Horner syndrome should therefore require prompt investigations to rule out carotid artery dissection. In patients with confirmed diagnosis, treatment should be started early to prevent permanent ocular or cerebral complications. Case Presentation Case 1: A 61-year-old woman presented with right temporal headache, an episode of transient visual loss and drooping of the right upper eyelid. Examination revealed anisocoria, which was more important in darkness. Reversal of anisocoria was observed after instilling drops of apraclonidine 0.5%. Neuro-imaging demonstrated intrapetrous ICAD. Headaches, eyelid ptosis and anisocoria all had resolved the next day. Apraclonidine pharmacologic testing a few weeks later was no longer dilating the smaller pupil. Case 2: A 48-year-old man presented with drooping of the right upper eyelid and right occipital headache and facial pain that all started one day after an intense yoga workout. Anisocoria was noticed upon examination, with topical cocaine 10% pharmacologic testing confirming a right Horner syndrome. Neuro-imaging revealed ICAD. The patient reported resolution of his eyelid ptosis a few days later. Eyelid ptosis and anisocoria had indeed resolved at a follow-up examination a few weeks later. However, cocaine drop testing still produced anisocoria, compatible with subclinical Horner syndrome. Conclusion Transient or subclinical Horner syndrome can be the presenting feature in ICAD; in such cases, the characteristic eyelid ptosis and anisocoria may be short-lived and resolve in only a few days. If suspected by clinical history, pharmacologic testing may be helpful in identifying subclinical cases

Fibro-odontome ameloblastique mandibulaire.

Ameloblastic fibro-odontoma is a rare and benign tumor. It usually affects young patients. This report describes the case of a ten year old child presenting an asymptomatic and slow-growing tumor located in the posterior region of the mandible. The course was normal and no recurrence was found after simple enucleation of the tumor.SCOPUS: ar.jinfo:eu-repo/semantics/publishe