Sharif Digital Repository

Immensity and profundity of mathematical logic have provided an opportunity for its interconnection with other branches of science, one of which is computer science where theory of dependent types and lambda calculus lounges amongst the area of their overlap. The former has been engendered for the sake of deepening the connection between mathematical logic and programming. On the other side, lambda calculus which is a formal system in mathematical logic and computer science, developed as a tool for formal computations, could also be counted as a programming discipline. It is the objective of this thsis to study the two aforementioned fields with emphasis on unification of higher-order... 

This research attempts to develop the optimal solution for an inventory problem consisting of a single machine which produces items some of which may be defective. We assume that no shortages are allowed and all defective items are to be reworked. Setup cost for rework and waiting time of defectives are considered. This research consists of two different parts. In the first part we consider two different policies where in the first policy in each cycle after the regular production the machine is setup for the rework of defectives of the same cycle. In the second policy several cycles constitute a period. All the defectives produced in the period are reworked in the last cycle of that period.... 

In the current century, an energy storage is one of the critical and important factors affecting on human life. Rechargeable batteries, specially Lithium ion batteries (LIBs), can be considered as ideal energy storage devices including various advantages e.g. high energy and power densities. In this work, Tin IV sulfide (SnS2) and its composites, making by conductive materials e.g. Reduced Graphene Oxide (SnS2@rGO), are prepared during two different synthesis methods consisting of Hydrothermal and Hot-bath, and their properties are investigated as anode material in LIB. The structural and electrochemical analyses demonstrated that the composite sample prepared by hot-bath method exhibited... 

Both handling and ride comfort play an important role in the performance and quality of a vehicle, and all the vehicle companies in addition to power and transmission system, pays special attention to these properties in the way of improving their products. This thesis is performed with the aim of study on effects of rubber bushing's characteristics of suspension system on handling behavior of a homeland built vehicle (pride). Role angle, slip angle, yaw rate and lateral acceleration are interrelated and are important quantities in studying on handling behavior of a vehicle. We have chosen slip angle as one these quantities and studied on effects of rubber bushing's characteristics on slip... 

Due to the data centers rapid growth and introduction of a new basic type of massive data processing platforms which requires accelerators to speedup computation and enhance the efficiency and reduce power consumption, using accelerators is inevitable. Communication and data transfer time between software and hardware is the most of time spent on the use of accelerators. By optimizing this part of the hardware / software platform, we have achieved substantial results in this area. The aim of our study is to organize a survey of real accelerator characteristics. To figure out its defects and main drawbacks, in addition to improving the overall efficiency of system. The implementation of... 

The PM2.5 particles are considered as one the most important pollutants of Tehran’s air due to their undesirable effect on health and environment. The particular matters which are in Tehran’s air are distributed from different sources. Because of lack of sufficient data about amount and chemical compounds of such matters in different areas, this study considers only concentration of particular matter and their composing elements in Sharif University, Tehransar, Mahalati, and Shahriyar station. By use of field measuring between 2015 to 2016 mass concentration of PM2.5 pollutant was calculated and then with the help of IC, GC/MS, and ICP chemical analysis which were conducted in University of... 

In recent years, global salt lakes have faced severe environmental challenges. Lake Urmia, the world’s second-largest hyper saline lake, is located in the northwest of Iran, has experienced a significant shrinkage in last years. Lake Urmia is a terminal lake where water enters through precipitation and rivers inflow and loses through evaporation. Analysis of long-term trends (1990-2018) using the Mann-Kendall test indicates no significant trend in precipitation, an increasing trend in evaporation, and a decreasing trend in river discharge. However, precipitation during 1990-1999 (beginning of accelerated lake drying) showed a decreasing trend. An investigation of the correlation between... 

We study the problem of preclustering a set $B$ of imprecise points in~$\Reals^d$: we wish to cluster the regions specifying the potential locations of the points such that, no matter where the points are located within their regions, the resulting clustering approximates the optimal clustering for those locations. We consider $k$-center, $k$-median, and $k$-means clustering, and obtain the various results. Then we study the higher order Voronoi Tessellations as an important concept in clustering area. Generalizing Lee’s inductive argument for counting the cells of higher order Voronoi tessellations in $\Reals^2$ to $\Reals^3$, we get precise relations in terms of Morse theoretic quantities... 

Fulfilling the demands of customers, used to be the main purpose of Supply Chain Network Designers. Soon after that, the environmental concerns created the concept of Reverse Logistic in order to prevent goods from being scattered in the environment after their disposal. Governmental regulations and people's concerns, forced the factories to gather the created pollutions of the environment. They gradualy confessed the positive impacts of these ruturns on their financials. The flow of forward and reverse logistics establishes a Closed-Loop in which the returning economical circumstances were transferd into original factories. Later, Open-Loops were created. In open-loops the returns have to... 

The water and energy demand increase as the population grows. Increased usage of energy leads to scarcity of available resources and limited absorption capacity of environment. Development of efficient and environmentally compatible energy conversion technologies are conceived as an important option for resolving pressing challenges. Compatibility with environment requires considerable reduction in the share of fossil fuels and efficient utilization of renewable energy sources. Hence, development of high-efficiency solar energy systems is becoming an important challenge in the energy sector. The present study is involved with development an integrated solar system based on the application of... 

Although inventory control under discrete demand in dynamic quantities and time intervals are very common in reality, existing literature has largely ignored them. In this thesis, we investigate the inventory control decisions in a two echelon supply chain. The vendor supplies a product to several retailers, buying discrete quantities in pre-determined time intervals. The order quantity and order cycles for each retailer can be different from others. We have developed a new efficient algorithm to find the optimal ordering policy involves the scheduling and the order quantity of vendor to his supplier to minimize his cost function in infinite time horizon. Moreover, we have designed a revenue...