SALSA-TEXT : self attentive latent space based adversarial text generation

Inspired by the success of self attention mechanism and Transformer architecture in sequence transduction and image generation applications, we propose novel self attention-based architectures to improve the performance of adversarial latent code- based schemes in text generation. Adversarial latent code-based text generation has recently gained a lot of attention due to their promising results. In this paper, we take a step to fortify the architectures used in these setups, specifically AAE and ARAE. We benchmark two latent code-based methods (AAE and ARAE) designed based on adversarial setups. In our experiments, the Google sentence compression dataset is utilized to compare our method with these methods using various objective and subjective measures. The experiments demonstrate the proposed (self) attention-based models outperform the state-of-the-art in adversarial code-based text generation.Comment: 10 pages, 3 figures, under review at ICLR 201

Efficient and Flexible First-Order Optimization Algorithms

Optimization problems occur in many areas in science and engineering. When the optimization problem at hand is of large-scale, the computational cost of the optimization algorithm is a main concern. First-order optimization algorithms—in which updates are performed using only gradient or subgradient of the objective function—have low per-iteration computational cost, which make them suitable for tackling large-scale optimization problems. Even though the per-iteration computational cost of these methods is reasonably low, the number of iterations needed for finding a solution—especially if medium or high accuracy is needed—can in practice be very high; as a result, the overall computational cost of using these methods would still be high. This thesis focuses on one of the most widely used first-order optimization algorithms, namely, the forward–backward splitting algorithm, and attempts to improve its performance. To that end, this thesis proposes novel first-order optimization algorithms which all are built upon the forward–backward method. An important feature of the proposed methods is their flexibility. Using the flexibility of the proposed algorithms along with the safeguarding notion, this thesis provides a framework through which many new and efficient optimization algorithms can be developed. To improve efficiency of the forward–backward algorithm, two main approaches are taken in this thesis. In the first one, a technique is proposed to adjust the point at which the forward–backward operator is evaluated. This is done through including additive terms—which are called deviations—in the input argument of the forward– backward operator. The deviations then, in order to have a convergent algorithm, have to satisfy a safeguard condition at each iteration. Incorporating deviations provides great flexibility to the algorithm and paves the way for designing new and improved forward–backward-based methods. A few instances of employing this flexibility to derive new algorithms are presented in the thesis.In the second proposed approach, a globally (and potentially slow) convergent algorithm can be combined with a fast and locally convergent one to form an efficient optimization scheme. The role of the globally convergent method is to ensure convergence of the overall scheme. The fast local algorithm’s role is to speed up the convergence; this is done by switching from the globally convergent algorithm to the local one whenever it is safe, i.e., when a safeguard condition is satisfied. This approach, which allows for combining different global and local algorithms within its framework, can result in fast and globally convergent optimization schemes

Pulmonary responses of rats exposed to titanium dioxide nanoparticles injected intratracheally

زمینه و هدف: نانوذرات دی اکسید تیتانیوم در سطح وسیعی در جهان کاربرد دارند. مطالعه­ی حاضر، برای ارزیابی مدت ماندگاری سمیت ریوی حاصل از نانوذرات دی اکسید تیتانیوم انجام شد. روش بررسی: در این مطالعه تجربی 60 سر موش صحرایی نر در 3 گروه (هر گروه شامل 4 زیر گروه 5 سری) تقسیم شدند. حیوانات در زیر گروه­های اول، دوم و سوم هر یک از گروه­ها به ترتیب 25، 50 و 100 میلی گرم بر کیلوگرم از نانو ذرات و در زیر گروه چهارم (گروه کنترل) هر گروه حجم برابری از نرمال سالین را به­صورت داخل نایی دریافت کردند. در روزهای 15، 30 و 45، به­ترتیب حیوانات گروه­های اول، دوم و سوم بی­هوش شدند. پس از گرفتن گراف های رادیولوژی حیوانات کشته و نمونه های خونی و بافتی جمع آوری شد. نتایج به­دست آمده از بررسی های هماتولوژی و بیوشیمیایی با آزمون آماری ANOVA و تست تعقیبی Tukey و نتایج حاصله از مطالعات پاتولوژی و رادیولوژی نیز با استفاده از آزمون آماری Fisher exact test مورد تجزیه و تحلیل آماری قرار گرفتند. یافته ها: نتایج، اختلاف معنی داری را در شمارش کلی گلبول های سفید، لنفوسیت ها، مونوسیت ها و گرانولوسیت ها و در فعالیت آنزیم های LDH و ALP را در روز 15 آزمایش نشان داد. بررسی های هیستوپاتولوژی و رادیولوژی دلالت بر پاسخ ریه ها به­صورت ضایعات آماسی وابسته به دوز مصرفی می کرد. این ضایعات بیشتر به شکل نفوذ سلول های آماسی و ضخیم شدن بافت بینابینی بود. نتیجه گیری: تحقیق حاضر پیشنهاد می کند که دوز مصرفی نقش مهمی را در سمیت ریوی بازی می کند و اثرات التهابی نانو ذرات دی اکسید تیتانیوم برای زمان محدودی باقی مانده و حیوان می تواند بعد از طی یک دوره زمانی مجدداً به حالت طبیعی باز گردد

Alternative inflationary scenario due to compact extra dimensions

The main goal of this paper is to give an alternative interpretation of space-like and time-like extra dimensions as a primary factor for inflation in the early universe. We introduce the 5-dimensional perfect fluid and compare the energy-momentum tensor for the bulk scalar field with space-like and time-like extra dimensions. It is shown, that additional dimensions can imply to negative pressure in the slow roll regime in the early higher-dimensional world.Comment: 6 page