Abstract: Embodiments of the present application are directed toward a focusing Schlieren technique that is capable of adding color-coded directional information to the visualization of density gradients. Other advantages of the technique can include that it does not require manual calibration, has a simple design and is sensitive enough to be used in compact experimental setups. Certain embodiments include the use of a color-coded source image that replaces the conventional source grid. The technique may benefit from a computer-controlled digital background, which is used for both illumination and display of color-coded source images.

Abstract: In one exemplary embodiment of the invention, a method for computing a resultant and a free term of a scaled inverse of a first polynomial v(x) modulo a second polynomial fn(x), including: receiving the first polynomial v(x) modulo the second polynomial fn(x), where the second polynomial is of a form fn(x)=xn±1, where n=2k and k is an integer greater than 0; computing lowest two coefficients of a third polynomial g(z) that is a function of the first polynomial and the second polynomial, where g(z)?i=0n?1(v(?i)?z), where ?0, ?1, . . . , ?n?1 are roots of the second polynomial fn(x) over a field; outputting the lowest coefficient of g(z) as the resultant; and outputting the second lowest coefficient of g(z) divided by n as the free term of the scaled inverse of the first polynomial v(x) modulo the second polynomial fn(x).

Abstract: In one exemplary embodiment of the invention, a method for computing a resultant and a free term of a scaled inverse of a first polynomial v(x) modulo a second polynomial fn(x), including: receiving the first polynomial v(x) modulo the second polynomial fn(x), where the second polynomial is of a form fn(x)=xn±1, where n=2k and k is an integer greater than 0; computing lowest two coefficients of a third polynomial g(z) that is a function of the first polynomial and the second polynomial, where g ? ( z ) ? = def ? ? i = 0 n - 1 ? ? ( v ? ( ? i ) - z ) , where ?0, ?1, . . . , ?n?1 are roots of the second polynomial fn(x) over a field; outputting the lowest coefficient of g(z) as the resultant; and outputting the second lowest coefficient of g(z) divided by n as the free term of the scaled inverse of the first polynomial v(x) modulo the second polynomial fn(x).

Abstract: An object of the present invention is to provide a mechanism for tamper detection of electronic devices (110) in closed units which is robust and low cost. The object is achieved by a method in an electronic device (110) for detecting if a cover (100) enclosing the electronic device (110) has been opened. The cover (100) comprises an enclosing assembly (250) which is adapted to fasten the cover (100) into a closed position. The electronic (device 110) comprises a non volatile memory (120). The non volatile memory (120) comprises a stored reference signature associated to the enclosing assembly (250) when the cover (100) was fastened into a closed position. The method comprises the following steps: (Creating 1003) a signature associated to the enclosing assembly (250). Comparing (1004) the created signature with the reference signature. Detecting (1007) that the cover 100 has been opened when the comparing (1004) results in a difference.

Abstract: A secure system for user authentication comprised of an authentication interface having a character dial and alignment markers is provided. A passcode input module receives user commands to move the character dial with respect to the alignment markers and to record a configuration of the characters with respect to the alignment markers, thereby creating alignment configuration data. A passcode generation module receives at least one of said alignment configuration data from passcode input module and generates a plurality of passcode hypotheses. An authentication module receives the passcode hypotheses and compares the passcode hypotheses with the passcodes of registered users stored in a data store. The passcode hypotheses are updated after each new alignment configuration data entered by the user. The authentication module authenticates a user upon finding a passcode hypothesis matching a stored passcode.

Abstract: A method for determining, for use in ciphers, all of the prime numbers within the large numeric series: 5, 6, 7, 8, 9, 10, 11, 12, . . . , n, the method including steps of setting n?=?n/6?; establishing the small numeric series, 6(1)?1, 6(1)+1, 6(2)?1, 6(2)+1, 6(3)?1, 6(3)+1, . . .

Abstract: The invention relates to securing of information utilising optical imaging technologies and more specifically to phase encryption and decryption of images. An image is encrypted into a mask having a plurality of mask resolution elements (Xm, Ym) by encoding the image using e.g. a phase mask with an encoded phase value ? (Xm, Ym) and an encoded amplitude value a (Xm, Ym), and by further encrypting the mask (using e.g. a spatial light modulator) by addition of an encrypting phase value ?c (Xm, Ym) to the encoded phase value ? (Xm, Ym) and by multiplication of an encrypting amplitude value ac (Xm, Ym) with the encoded phase value a (Xm, Ym).

Abstract: A system for determining a location of a selected vehicle from which an alarm signal is generated which includes a fixed array of cellular sites each site having a wireless signal detecting and generating units each of which is capable of receiving an input alarm signal having a signal strength which is a function of the distance between the position of the vehicle generating the alarm signal and the position of each of the wireless signal detecting units. Each unit also is capable of transmitting an output signal which is a function of the strength of the input alarm signal.

Abstract: This apparatus and method protects software from unauthorized distribution and use, by utilizing the fact that holograms and other optical effects-producing media are extremely difficult to copy. A hologram, series of holograms, or other optical media, are used to create an "optical software key". When queried by a computer program, the program user, with the help of the optical key, reads a code (or codes). When the appropriate code is input to the program, access (or continued access) is then allowed.

Abstract: The encoder/decoder comprises a spherical body on which is provided a plurality of different letters and/or numerals. Connecting means in the form of three circular members sharing the same axis encompass the sphere, two defining two parallel sighting hoops and the third defining a sighting ring. The connecting means are mounted on a support body so that the relative rotation of the connecting means and the body can be effected. In use, the body is rotated until two specified indicia lie usually between the two sighting hoops in a specified order. Then, one or more indicia are read from the sighting ring. The encoder/decoder may be used to protect computer software against copying, and may also be used to hinder unauthorized access to remote computer systems. Thus, the number of individuals using a system can be limited to the number interrogating the user, can determine whether he has in his possession a suitable encoder/decoder such as outlined above.