Difference target propagation

Backpropagation has been the workhorse of recent successes of deep learning but it relies on infinitesimal effects (partial derivatives) in order to perform credit assignment. This could become a serious issue as one considers deeper and more non-linear functions, e.g., consider the extreme case of non-linearity where the relation between parameters and cost is actually discrete. Inspired by the biological implausibility of Backpropagation, this thesis proposes a novel approach, Target Propagation. The main idea is to compute targets rather than gradients, at each layer in which feedforward and feedback networks form Auto-Encoders. We show that a linear correction for the imperfectness of the Auto-Encoders, called Difference Target Propagation is very effective to make Target Propagation actually work, leading to results comparable to Backpropagation for deep networks with discrete and continuous units, Denoising Auto-Encoders and achieving state of the art for stochastic networks. In Chapters 1, we introduce several classical learning rules in Deep Neural Networks, including Backpropagation and more biological plausible learning rules. In Chapters 2 and 3, we introduce a novel approach, Target Propagation, more biological plausible learning rule than Backpropagation. In addition, we show that Target Propagation is comparable to Backpropagation in Deep Neural Networks.L'algorithme de r etropropagation a et e le cheval de bataille du succ es r ecent de l'apprentissage profond, mais elle s'appuie sur des e ets in nit esimaux (d eriv ees partielles) a n d'e ectuer l'attribution de cr edit. Cela pourrait devenir un probl eme s erieux si l'on consid ere des fonctions plus profondes et plus non lin eaires, avec a l'extr^eme la non-lin earit e o u la relation entre les param etres et le co^ut est r eellement discr ete. Inspir ee par la pr esum ee invraisemblance biologique de la r etropropagation, cette th ese propose une nouvelle approche, Target Propagation. L'id ee principale est de calculer des cibles plut^ot que des gradients a chaque couche, en faisant en sorte que chaque paire de couches successive forme un auto-encodeur. Nous montrons qu'une correction lin eaire, appel ee Di erence Target Propaga- tion, est tr es e cace, conduisant a des r esultats comparables a la r etropropagation pour les r eseaux profonds avec des unit es discr etes et continues et des auto- encodeurs et atteignant l' etat de l'art pour les r eseaux stochastiques

Effective use of negative space in graphic design

This thesis will investigate the potential use of effective negative space to improve the readability of text typography in graphic design. Negative space in two-dimensional design is also referred to as white space -- which is void of text or graphics. Negative space is more than just the background of a design. This thesis will demonstrate negative space as an element of design itself and develop a systematic approach to address negative space as it occurs in the following: margins, background, space for the eye to rest, signal that there is a break or end in the communication, variation in space -- passive vs. dynamic, implied space

Attrition rate of iron ore in the gas-solid fluidized beds with the wide size distribution

The effects of superficial gas velocity (Ug = 1.25 – 3.00 m/s) and distributor hole size (8.0 – 12.4 mm) on the attrition rate of iron ore in a gas-solid fluidized bed with 0.076 m ID ´ 3.7 m height with or without circulation were investigated. The particle density and the Sauter mean diameter of fresh iron ore were 3,705 kg/m3 and 357 m, respectively. When the kinetic energy rate from the orifice was equal or greater than 180 J/s, the trend of attrition rate could be determined. The attrition rate was determined by measuring the fractional mass of fine particle formation (- 500 m fraction) during 30 min without circulation. In experiments with circulation, the attrition rate was determined by measuring a different threshold size, 63 m. The attrition rate increases with increasing kinetic energy rate from the orifice (J/s). The kinetic energy rate from the orifice was calculated using the mass flow rate and orifice nozzle velocity. The correlation of attrition rate with the kinetic energy rate from the orifice was. When the bed height rapidly decreased below the jet length under very severe conditions, the attrition rate did not follow the correlation

Current-induced domain wall motion in a nanowire with perpendicular magnetic anisotropy

We study theoretically the current-induced magnetic domain wall motion in a metallic nanowire with perpendicular magnetic anisotropy. The anisotropy can reduce the critical current density of the domain wall motion. We explain the reduction mechanism and identify the maximal reduction conditions. This result facilitates both fundamental studies and device applications of the current- induced domain wall motion

Effects Of HPWSS On Employee’ Attitude For Korean Firms: The Mediating Role Of Human Resource Competency And The Moderating Role Of Organization Culture

The purpose of this paper is to examine the black box by which high performance work systems (HPWSs) affect employee’s attitude. It attempts to show the mediating effect of human resource (HR) competency in the HPWSs-job attitude link, and the moderating effect of organization culture. More specifically, we propose that HPWSs have a positive effect on the both job satisfaction and HR competency, and that HR competency mediates the relationship between HPWSs and job satisfaction. Further, we propose that adhocracy culture in organization strengthens such relationships between HPWSs and HR competency as well as between HPWSs and job satisfaction. We use a nationally representative data set from Korea (firm-level samples: 215 firms, employee-level samples: 5577 employees) for testing the hypotheses. Results indicated support for the hypothesized that positive association between HPWSs and HR competency and between HPWSs and job satisfaction. HR competency has a partial mediating effect in the HPWS-job attitude link. The results were supportive of organization culture of the impact of HPWSs on HR competency and job satisfaction. Limitations of the study and implications for future research are discussed.