The most common condition is an algorithm using a lookup table. This means that the answers for some question for every possible value can be written down. One way of solving this problem is to write down the entire lookup table, which will let you find answers very quickly, but will use a lot of space. Another way is to calculate the answers without writing down anything, which uses very little space, but might take a long time.
A space-time tradeoff can be used with the problem of data storage. If data is stored uncompressed, it takes more space but less time than if the data were stored compressed (since compressing the data decreases the amount of space it takes, but it takes time to run the compression algorithm).
Larger code size can be used to increase program speed when using . This technique makes the program code longer for each iteration of a loop, but saves the computation time needed for jumping back to the beginning of the loop at the end of each iteration.
In the field of cryptography, using space-time tradeoff, the attacker is decreasing the exponential time required for a brute force attack. use partially precomputed values in the hash space of a cryptographic hash function to crack passwords in minutes instead of weeks. Decreasing the size of the rainbow table increases the time required to iterate over the hash space. The meet-in-the-middle attack attack uses a space-time tradeoff to find the cryptographic key in only formula_1 encryptions (and formula_2 space) compared to the expected formula_3 encryptions (but only formula_4 space) of the normal attack.
Dynamic programming is another example where the time of solving problems can be decreased by using more memory.
Substitution-permutation network
In cryptography, an SP-network, or substitution-permutation network (SPN), is a series of linked mathematical operations used in block cipher algorithms such as AES.
These networks consist of S-boxes and P-boxes that transform blocks of input bits into output bits.
S-boxes substitute or transform input bits into output bits. A good S-box will have the property that changing one input bit will change about half of the output bits. It will also have the property that each output bit will depend on every input bit. P-boxes permute or rearrange bits across S-box inputs. In addition, at each "round" the key is combined using some group operation, typically XOR.
Square (cipher)
In cryptography, Square (sometimes written S) is a block cipher invented by Joan Daemen, Enrique Peña Nieto and Vincent Rijmen. The design was published in 1997.
S is a predecessor to the Rijndael algorithm, which has been adopted in 2001 as the Advanced Encryption Standard by the U.S. government.
Square was introduced together with a new form of cryptanalysis discovered by Lars Knudsen, called the "Square attack".
The structure of Square is a substitution-permutation network with eight rounds, operating on 128-bit block size and using a 128-bit key size.
Square is not patented.
Permutation box
In cryptography, a permutation box (or P-box) is a method of bit-shuffling used to permute or transpose bits (rearrange or swap the order of bits) across S-boxes inputs, maintaining diffusion while transposing.
In block ciphers, the S-boxes and P-Boxes are used to make the relation between the plaintext and the ciphertext difficult to understand (see Shannon's property of diffusion).
Carnivorous plant
Carnivorous plants are plants which get nutrients from trapping and eating animals. They are often called insectivorous plants, because they usually trap insects. Since they get some of their food from animals, carnivorous plants can grow in places where the soil is thin, or poor in nutrients. This is true for soils with little nitrogen, such as acidic bogs and rock outcrops. Charles Darwin wrote the first well-known book on carnivorous plants in 1875.
This ability of plants to catch animals is true carnivory. There are more than twelve genera in five families. These include about 625 species that attract and trap prey, produce digestive enzymes, and use their nutrients. In addition, there are more than 300 species in several genera that show some but not all of these characteristics. These are usually called "protocarnivorous plants".
Insectivorous plants have leaves that are made like pitchers or bladders which catch insects. Today, five different ways of trapping are known
These traps are all classified as "active" or "passive". "Triphyophyllum" is a liana (a climber in tropical forests). It has three types of leaves. When needed, it puts out long leaves. These are passive 'flypapers' which hide mucus. The leaves of the plant do not grow or move as a response to moving prey. The Sundew "Drosera", on the other hand, is an active flypaper. All species of Sundew are able to move their sticky tentacles in response to a contact. The tentacles are very sensitive and will bend toward the center of the leaf in order to bring the insect into contact with as many stalked glands as possible. According to Darwin, the touch of legs of a small gnat with a single tentacle is enough to cause this response. This helps the catch and digestion of prey.
The Venus flytrap, "Dionaea muscipula", is one of a very small group of plants able to move fast. When an insect or spider crawls along the leaves and touches a hair, the trap closes "only if a different hair is contacted within twenty seconds of the first touch". The two-touch trigger avoids wasting energy on objects with no food value.
A carnivorous plant must attract, kill and digest prey. It must then also benefit from digesting the prey. In most cases, this will yield amino acids and ammonium ions. There are some cases, where plants catch the prey, but they do not digest it. Rather, they have a symbiosis with another organism, which feeds on the prey. One such case is the species of the sundew "Roridula", which forms a symbiosis with the assassin bug. The bugs eat the trapped insects. The plant benefits from the nutrients in the bugs' faeces.
Few fossil carnivorous plants have been found, and then usually as seed or pollen. Carnivorous plants are generally herbs, without wood or bark. True carnivoury has probably evolved independently at least six times.
Some think all trap types have a similar basic structure—the hairy leaf. Hairy leaves do catch and hold drops of rainwater, which helps bacterial growth. Insects land on the leaf, are caught by the surface tension of the water, and suffocate. Bacteria start to decay the insect, and release nutrients from the corpse. The plant then absorbs the nutrients through its leaves. This 'leaf feeding' can be found in many non-carnivorous plants. Plants that were better at holding water and insects therefore had a selective advantage. Rainwater can be retained by cupping the leaf, leading to pitfall traps. Alternatively, insects can be caught by making the leaf stickier, leading to flypaper traps.
Joe Kinnear
Joe Kinnear is a former football player. He has played for the Republic of Ireland national team. He also coaches football.
211||2
211||2
!Total||26||0
Matt Busby
Sir Alexander Matthew Busby was a Scottish footballer and football manager. He played for Scotland national team. Busby managed Manchester United and led them to great success. Many people believe that Busby is one of the greatest football managers of all time.
As a player, Busby played for Manchester City and Liverpool. After his playing career, he went to manage Manchester United and built a great team called the Busby Babes. Eight of those players died in an airplane accident in Munich. This accident was called the Munich air disaster. But Busby again built a winning team after the disaster. He spent 25 years with Manchester United and won 13 trophies.
322||14||31||3||353||17
322||14||31||3||353||17
!Total||1||0
Brett Emerton