Renewing the respect for similarity

In psychology, the concept of similarity has traditionally evoked a mixture of respect, stemming from its ubiquity and intuitive appeal, and concern, due to its dependence on the framing of the problem at hand and on its context. We argue for a renewed focus on similarity as an explanatory concept, by surveying established results and new developments in the theory and methods of similarity-preserving associative lookup and dimensionality reduction—critical components of many cognitive functions, as well as of intelligent data management in computer vision. We focus in particular on the growing family of algorithms that support associative memory by performing hashing that respects local similarity, and on the uses of similarity in representing structured objects and scenes. Insofar as these similarity-based ideas and methods are useful in cognitive modeling and in AI applications, they should be included in the core conceptual toolkit of computational neuroscience. In support of this stance, the present paper (1) offers a discussion of conceptual, mathematical, computational, and empirical aspects of similarity, as applied to the problems of visual object and scene representation, recognition, and interpretation, (2) mentions some key computational problems arising in attempts to put similarity to use, along with their possible solutions, (3) briefly states a previously developed similarity-based framework for visual object representation, the Chorus of Prototypes, along with the empirical support it enjoys, (4) presents new mathematical insights into the effectiveness of this framework, derived from its relationship to locality-sensitive hashing (LSH) and to concomitant statistics, (5) introduces a new model, the Chorus of Relational Descriptors (ChoRD), that extends this framework to scene representation and interpretation, (6) describes its implementation and testing, and finally (7) suggests possible directions in which the present research program can be extended in the future

Spiking neurons with short-term synaptic plasticity form superior generative networks

Spiking networks that perform probabilistic inference have been proposed both as models of cortical computation and as candidates for solving problems in machine learning. However, the evidence for spike-based computation being in any way superior to non-spiking alternatives remains scarce. We propose that short-term plasticity can provide spiking networks with distinct computational advantages compared to their classical counterparts. In this work, we use networks of leaky integrate-and-fire neurons that are trained to perform both discriminative and generative tasks in their forward and backward information processing paths, respectively. During training, the energy landscape associated with their dynamics becomes highly diverse, with deep attractor basins separated by high barriers. Classical algorithms solve this problem by employing various tempering techniques, which are both computationally demanding and require global state updates. We demonstrate how similar results can be achieved in spiking networks endowed with local short-term synaptic plasticity. Additionally, we discuss how these networks can even outperform tempering-based approaches when the training data is imbalanced. We thereby show how biologically inspired, local, spike-triggered synaptic dynamics based simply on a limited pool of synaptic resources can allow spiking networks to outperform their non-spiking relatives.Comment: corrected typo in abstrac

A Study of Factors Affecting the Renewal of Health Insurance Policy

Health insurance policies are generally one-year policies and to remain part of the insurance poll, policyholders are required to renew their policies each year. Understanding the factors that affect the demand and renewal decisions to continue in health insurance programme is imperative for future growth and development of the insurance sector. We extend our previous work on factors affecting the decision to purchase health insurance to understand the factors affecting the renewal of insurance policy. We find the factors affecting health insurance renewal are not the same as factors affecting health insurance purchase decision. This has implications for insurance providers. The study also suggests customer satisfaction as an important factor influencing the renewal decision of policyholder.

Experimental evidence for the essential identity of the selective and normal photo-electric effects

In the fall of 1913, while studying the photo-electric properties of freshly cut surfaces of the alkali metals in extreme vacua, we observed that immediately after first cutting, the fresh surface of sodium showed very large photo-sensitiveness when tested with monochromatic light of wave length 5461 A., even when the vacuum was of the order 10(-6) mm. as measured by a McLeod gauge. But after several weeks of experimenting and many cuttings a condition was reached in which a freshly cut surface was completely insensitive when illuminated with this wave length. The lost sensitiveness reappeared, however, in the course of not more than two minutes after cutting, and grew rapidly to a very large value in fifteen or twenty minutes. When the gas pressure was of the order of 0.01 mm. the same phenomenon occurred but the rise to a maximum value was less rapid. From these results we began to surmise that photo-electric currents must be due to the influence of some active gas, which diffused from the walls to the metal and whose action upon the surface was retarded by the presence of an inert gas

Turkey's competitiveness in the European Union: A comparison with five candidate countries - Bulgaria, The Czech Republic, Hungary, Poland, Romania - and the EU15

The main purpose of this paper is to examine the international competitiveness of the Turkish economy and the structure of specialisation in foreign trade in comparison with the five EU candidate countries Bulgaria, the Czech Republic, Hungary, Romania, Poland and the EU/15. This research work attempts to find out Turkey's ability to overcome difficulties and challenges that might arise from the hard competition with the enlarged EU, mainly in the field of foreign trade.International Competitiveness of Turkish Economy, EU 15, EU Candidate Countries

“Total and Radical Liberation”: The Religious and Philosophical Background of Volodymyr Vynnychenko’s Revolutionary Ideas

The article explores the religious and philosophical origins of Volodymyr Vynnychenko’s ideas of “honesty with oneself,” “omnilateral liberation,” and “concordism.” Two treatises, Vidrodzhennia natsii (Rebirth of a Nation, 1919–1920) and Konkordyzm. Systema buduvannia shchastia (Concordism. A System of Building Happiness, 1938–1945), illustrate the development of Vynnychenko’s worldview. In the first work, social revolution was considered as the answer to human problems, while, in the second, such a solution was found in becoming one with the universe. Despite his negative attitude towards religion, Volodymyr Vynnychenko actively used religious images and patterns in his writings. For instance, criticizing Christianity for its dogmatism, he nevertheless created his codex of thirteen rules of concordism, which had to harmonize the unbalanced forces of mankind with the universe. In this context, particular attention is paid to the significant influence of pagan concepts on Vynnychenko’s thinking