Do SAT Problems Have Boiling Points？
The Boolean Satisfiability problem, called SAT for short, is the problem of determining if a set of constraints involving Boolean (True/False) variables can be simultaneously satisfied. SAT solvers have become an integral part in many computations that involve making choices subject to constraints, such as scheduling software, chip design, decision making for robots (and even Sudoku!). Given their practical applications, one question is when SAT problems become hard to solve. The problem difficulty depends on the constrainedness of the SAT instance, which is defined as the ratio of the number of constraints to the number of variables. Research in the early 90’s showed that SAT problems are easy to solve both when the constrainedness is low and when it is high, abruptly transitioning (“boiling over” ) from easy to hard in a very narrow region in the middle. My project is aimed at verifying this surprising finding. I wrote a basic SAT solver in Python and used it to solve a large number of randomly generated 3SAT problems with given level of constrainedness. My experimental results showed that the percentage of problems with satisfying assignment transitions sharply from 100% to 0% as constrainedness varies between 4 and 5. Right at this point, the time taken to solve the problems peaks sharply. Similar behavior also holds for 2SAT and 4SAT. Thus, SAT problems do seem to exhibit phase transition behavior; my experimental data supported my hypothesis.
Universal computing sorting machine
The purpose of the study was to develop and create a semi-automatic multi-purpose sorting and counting machine of standard articles. Currently, there is a problem of equipping industrial enterprises as well as small trade companies and large retailers with computing sorting machines of standard products of a certain shape. We would like to fill this missing link up with a simple, compact and inexpensive device. Procedures The proposed research consisted of a consistent design of a virtual model of the device and its electronic-mechanical implementation. The virtual model is simulated by a computer program "SolidWorks" object, which graphically shows the operation of the future device. In the development of the computing sorting device standard electronic devices and their associated software have been used. The created simplified real model demonstrates the basic principles and characteristics of the proposed device. Data As an example for the implementation of the concept device a computing device for sorting coins, in circulation in Russia has been created. As a basic principle of sorting objects by their geometric and weight characteristics were used. It is important that the device is focused on the correct form of the objects of sorting (balls, rings, coins, regular polyhedrons, screws, nuts, etc). To confirm the effectiveness of the computing device of this type of sorting, a series of tests of counting of objects manually have been carried out . The effectiveness of the device is determined by comparing the time characteristics of manual and automatic sorting. Findings and conclusions As a result of research and work performed, we have concluded that: 1) The proposed device can be used in various industries. (for example, while sorting ball bearings.) 2) Such a computing sorting device may find it's application in various commercial enterprises: to assist cashiers in retail ATMs. 3) Can be used in payment terminals. 4) 4) After a certain modernization of the device it can be used for money encashment.
My parking space ,, My Right !!
An Automatic Fine system for the handy-caps parking spaces We human beings Are developing creatures, And we believe that the Importance of scientific innovations depends on how much can they contribute in humanities services. Me and my friend worked so hard to present an Invention or a system that is going to make people lives better. In this point of view that we humans believe in. We work hard and we present Inventions, science fears, and new Ideas by a purpose and an intention that those thoughts, Inventions, Ideas, researches …etc. Will make us better people And will help in building a brighter future for mankind. Invention identity Name of the invention: My parking space,, My Right !! Components: Ultrasonic sensor, color sensor, RFID sensor and reader, buzzer, lights, NXT robot, conductive means (wires) How does the invention work? Operating Process The first point we want to make it clear to you that we have two stages: now (present) and later in real life. For the moment : We are using an educational robot (NXT mindstorm) with a programme from our design , using the Ultrasonic sensor to know if there is a car parking or not then using a color sensor to determine if the car is allowed to park or not And if not then write a ticket and a fine but before that it gives an alarm to notice the driver. The main objective of the invention We want to help maintaining the lost rights for the handy-cap people in their parking spots. Because we gave them less than what the numbers say we should of give them so we didn't give them what they deserve and we came at the same time and steeled it from them. this invention is used: usage fields This invention will be used in the handy-caps parking spaces as well as they will help of the economic. It can be employed and used instead of a lot of security persons or traffic Police department. The future vision of the invention It can be combined in a one small unit and with touch panels to know if there is a car parking or not, RFID to determine if the car is allowed or not to park in this space and a camera to know the exact car or maybe by reading the electronic chip in the cars plate .
Applications of Biofuel Technologies for Third World Countries
Innovative, inexpensive, sustainable fuel for cooking and light can be produced with an anaerobic digestion biogas system. A biodigester was designed from parts that are locally available to purchase and maintain in a developing nation. The prototype was designed, built and the engineering was approved and tested. Research and testing of techniques used to produce biogas were recorded and analyzed. The digester successfully produced enough biogas to connect to a stove and burn. Research and testing continued on different ways to pressurize the biogas. A burn time of eleven minutes was recorded. A Bunsen burner was designed, again from locally available parts, in order to enhance the flame to use for cooking. The designed digester and burner worked satisfactorily to burn the biogas collected in the system. Using small scale tests, additional research and testing continued on the most efficient production of the biogas. Figure 1 shows the results of the small scale biogas testing. The results from the small scale testing showed that the best variables for producing biogas are using school compost, ie apples, bananas, oranges, cucumbers, grapefruit, grapes etc, which has been blended to acquire the most surface area with a 1:1 ratio. Figure 3 shows the results of a sample of methane (first three peaks) and of the biogas that was produced (last two peaks). The first peak is the nitrogen and the oxygen in the sample. The second peak is the methane and the third peak is carbon dioxide. The first biogas sample that was tested had no methane so there was an absence of the second peak. This was similar for Figures 4 and 5. Figure 6 shows a sample of the final biogas product which is producing methane as shown by the blue circle. Figures 3 through 5 lack a methane peak due to leaks in the biogas system and limited time within testing periods. The hypothesis was proved correct. An innovative, inexpensive, sustainable fuel for cooking and light using an anaerobic digestion system that can be built completely in developing nations such as Honduras was created. The biogas was ignited using a stove which provided heat for cooking. The biogas was not tested using a light; however, since the biogas can burn, this is theoretically possible. The final system achieved these goals.