Ladder Siamese Network: a Method and Insights for Multi-level Self-Supervised Learning

Siamese-network-based self-supervised learning (SSL) suffers from slow convergence and instability in training. To alleviate this, we propose a framework to exploit intermediate self-supervisions in each stage of deep nets, called the Ladder Siamese Network. Our self-supervised losses encourage the intermediate layers to be consistent with different data augmentations to single samples, which facilitates training progress and enhances the discriminative ability of the intermediate layers themselves. While some existing work has already utilized multi-level self supervisions in SSL, ours is different in that 1) we reveal its usefulness with non-contrastive Siamese frameworks in both theoretical and empirical viewpoints, and 2) ours improves image-level classification, instance-level detection, and pixel-level segmentation simultaneously. Experiments show that the proposed framework can improve BYOL baselines by 1.0% points in ImageNet linear classification, 1.2% points in COCO detection, and 3.1% points in PASCAL VOC segmentation. In comparison with the state-of-the-art methods, our Ladder-based model achieves competitive and balanced performances in all tested benchmarks without causing large degradation in one

Economic policy of German civil administration in occupied Latvia 1941 - 1944

Promocijas darbā „Vācu civilās pārvaldes ekonomiskā politika okupētajā Latvijā 1941 – 1944” tiek pētīta vācu ekonomiskā politika Latvijas ģenerālapgabalā, vācu civilās okupācijas pārvaldes pastāvēšanas laikam nosakot pētījuma hronoloģisko ietvaru. Darba galvenā uzmanība tiek pievērsta okupācijas varas saimnieciskai koncepcijai un tās izpausmēm ekonomikā, tostarp lauksaimniecības politikā, ilgstošajā reprivatizācijas jautājumā, rūpniecībā. Skatīta tiek arī Latvijas Zemes pašpārvaldes loma ekonomiskajos procesos, Latvijas iedzīvotāju iesaistīšana sabiedriskajos darbos, gūstekņu nodarbināšana un to kopējā nozīme ekonomikā, kā arī Latvijas iedzīvotāju attieksme pret okupācijas varu saimniecisko jautājumu kontekstā. Salīdzinošā formā tiek skatīts jautājums par kopējo un atšķirīgo Latvijas, Lietuvas un Igaunijas ģenerālapgabalu ekonomikā. Latvija, ekonomika, 2. Pasaules karšDoctoral thesis „Economic policy of German civil administration in occupied Latvia 1941 – 1944” investigates German economic policy in General District of Latvia, whereby the timeframe of German civil administrations existence, sets the chronological borders of the research. Particular attention in the thesis is paid to the economic conception of German representatives and its manifestation in the economy, including in agricultural policy, lengthy reprivatisation process and industry. Also the role of Latvian Self-government in the economy is discussed. Other topics include involvement of Latvian population in public work and their attitude towards Germans. German economic policy in Latvia, Estonia and Lithuania is comparatively analysed searching for similarities and differences. Latvia, economy, 2 World Wa