Cortical Learning of Recognition Categories: A Resolution of the Exemplar Vs. Prototype Debate

Do humans and animals learn exemplars or prototypes when they categorize objects and events in the world? How are different degrees of abstraction realized through learning by neurons in inferotemporal and prefrontal cortex? How do top-down expectations influence the course of learning? Thirty related human cognitive experiments (the 5-4 category structure) have been used to test competing views in the prototype-exemplar debate. In these experiments, during the test phase, subjects unlearn in a characteristic way items that they had learned to categorize perfectly in the training phase. Many cognitive models do not describe how an individual learns or forgets such categories through time. Adaptive Resonance Theory (ART) neural models provide such a description, and also clarify both psychological and neurobiological data. Matching of bottom-up signals with learned top-down expectations plays a key role in ART model learning. Here, an ART model is used to learn incrementally in response to 5-4 category structure stimuli. Simulation results agree with experimental data, achieving perfect categorization in training and a good match to the pattern of errors exhibited by human subjects in the testing phase. These results show how the model learns both prototypes and certain exemplars in the training phase. ART prototypes are, however, unlike the ones posited in the traditional prototype-exemplar debate. Rather, they are critical patterns of features to which a subject learns to pay attention based on past predictive success and the order in which exemplars are experienced. Perturbations of old memories by newly arriving test items generate a performance curve that closely matches the performance pattern of human subjects. The model also clarifies exemplar-based accounts of data concerning amnesia.Defense Advanced Projects Research Agency SyNaPSE program (Hewlett-Packard Company, DARPA HR0011-09-3-0001; HRL Laboratories LLC #801881-BS under HR0011-09-C-0011); Science of Learning Centers program of the National Science Foundation (NSF SBE-0354378

Turkey's 'New' Foreign Policy towards Eurasia

Cataloged from PDF version of article.Two geographers specializing in Turkey’s international relations examine the reframing of foreign policy issues under the country’s Justice and Development Party (JDP; also known by its Turkish acronym AKP), in power since 2002. After first locating the JDP within Turkey’s current political landscape, the authors investigate how notions of civilizational geopolitics have led to a “new geographic imagination” under JDP that has influenced foreign policy thinking. The authors argue that JDP foreign policy exhibits some continuity with that of earlier governments in terms of activist policies toward Central Eurasia (comprising the Middle East, Central Asia, and Transcaucasia), but are based on a new conceptual foundation that views Turkey not as part of Western civilization but as the emerging leader of its own “civilizational basin” (consisting of the former Ottoman territories plus adjoining regions inhabited by Muslim and Turkic peoples). They then explore the implications for Turkey’s future relations with the Central Eurasian region (of which Turkey is assumed to be the leader) and countries of the West (viewed now as “neighbors” but no longer “one of us”). Journal of Economic Literature, Classification Numbers: F500, F530, O180. 4 tables, 63 references. Key words: Turkey, Eurasia, civilizational geopolitics, Justice and Development Party, Central Asia, Middle East, Transcaucasia, foreign policy, oil pipelines, natural gas pipelines

Global Asymptotic Stability for Discrete Single Species Population Models

We present some basic discrete models in populations dynamics of single species with several age classes. Starting with the basic Beverton-Holt model that describes the change of single species we discuss its basic properties such as a convergence of all solutions to the equilibrium, oscillation of solutions about the equilibrium solutions, Allee’s effect, and Jillson’s effect. We consider the effect of the constant and periodic immigration and emigration on the global properties of Beverton-Holt model. We also consider the effect of the periodic environment on the global properties of Beverton-Holt model

Implementation of a simplified method for actuation of ferrofluids

This paper was presented at the 3rd Micro and Nano Flows Conference (MNF2011), which was held at the Makedonia Palace Hotel, Thessaloniki in Greece. The conference was organised by Brunel University and supported by the Italian Union of Thermofluiddynamics, Aristotle University of Thessaloniki, University of Thessaly, IPEM, the Process Intensification Network, the Institution of Mechanical Engineers, the Heat Transfer Society, HEXAG - the Heat Exchange Action Group, and the Energy Institute.Magnetic actuation of ferrofluids is an emergent field that will open up new possibilities in various fields of engineering. The quality and topology of the magnetic field that is being utilized in such systems is determinant in terms of flow properties, flow rates and overall efficiency. Determining the optimal magnetic field topology to achieve the desired results, and determining the methods by which these magnetic fields are to be generated are central problems of obtaining the desired flow. A healthy comparison of various magnetic field topologies requires a varied set of examples from the most simplified to most sophisticated. Such comparisons are necessary to have a well grounded starting point. This study focuses on a particular pump design that employs a simplified magnetic field topology to obtain ferrofluid flow. The results of this paper such as flow and pressure difference are intended to form a baseline for future reference.Sabancı University Internal Research Grant, no: IACF09-0064

Production of fish finger from sand smelt (Atherina boyeri, RISSO 1810) and determination of quality changes

In this study, changes of chemical, microbiological load and sensory properties of fish fingers prepared from sand smelt (Atherina boyeri, RISSO 1810) were investigated during storage (for 6 months at -18°C). The fish finger nutritional composition changed with the fish finger process. The changes in moisture, crude protein, crude fat and crude ash components between fresh sand smelt and fish fingers were found to be significant at P < 0.05. C18:1 w-9 and C18:2 w-6 increased with pre-frying process. The values of pH, total volatile basic nitrogen (TVB-N) and thiboarbutiric acid (TBA) at the end of the storage were determined as 6.737 ± 0.012, 19.583 ± 0.087 mg/100 g and 0.293 ± 0.013 μgMDA/g, respectively. According to sensory analyses scores, the fish fingers were fondly prefered by panellists. According to the results of the chemical, sensory and microbiological quality in fish, fish fingers were found within the acceptable limits during frozen storage for 6 months.Key words: Sand smelt, Atherine boyeri, fish finger, chemical quality, sensory quality, fatty acids

Modelling Word Associations with Word Embeddings for a Guesser Agent in the Taboo City Challenge Competition

In the Taboo City Challenge, artificial agents should guess the names of cities from simple textual hints and are evaluated with games played by humans. Thus, playing the games successfully requires mimicking associations that humans have with geographical locations. In this paper, an architecture is proposed that calculates the associative similarity between a city and a hint from a semantic vector space. The semantic vector space is created using the Skip-gram hierarchical softmax model, from a tailored corpus about travel destinations. We investigate the effect of varying training parameters and introduce a targeted corpus annotation method that significantly improves performance. The results on a dataset of 149 games indicate that the proposed architecture can guess the target city with up to 22.45% accuracy — a substantial improvement over the 4.11% accuracy achieved by the baseline architecture

Optimal Reactive Extraction of Valeric Acid from Aqueous Solutions Using Tri-n-propyl amine/Diluent and Dibenzyl amine/Diluent Systems

Reactive extraction of valeric acid from water by tri-n-propyl amine (TPA) and dibenzyl amine (DBA) dissolved in polar oxygenated aliphatic diluents (diethyl sebacate, diethyl succinate, diethyl malonate, ethyl caprylate, ethyl valerate and isoamyl alcohol) has been studied at T = 298 ± 0.2 K and Pp =101.3 ± 0.7 kPa . Distribution data have been subjected to formulation of an optimization structure for effective acid separation. The optimization approach uses separation ratio R and synergistic enhancement SE factors to efficiently identify optimum extraction ranges. Among the examined aliphatic ester and alcohol diluents, monoesters exhibit higher solvation efficiency comprising acid1–amine1 complex formation, while isoamyl alcohol yields larger loading factors. The uptake capacity of the amine/diluent system is ranging in the order TPA > DBA. Modeling efforts based on the mass-action law principles have shown considerable success. The mass action law chemodel and modified Langmuir approach are quite accurate yielding mean errors of 0.9 % and 0.7 %, respectively