COLLISION

Virtual reality applications refer to the use of com- puters to simulate a physical environment in such a way that humans can readily visualize, explore, and interact with "objects" in this environment. The design of virtual scenes requires realistic physically based simulation algorithms and in particular effi- cient collision detection routines. Collision detection prevent penetrations between objects. This paper presents an overview of the collision detection procedures for rigid bodies. It divides those procedures in two families that form a general hybrid collision detection algorithm. The first family is used in the first phase known as broad phase that roughly detects collision. The second family is used in the second one known as narrow phase that exactly detects if collision occurs.

Densities (ρ), ultrasonic speeds (u), and excess molar volumes () of binary mixtures of some aromatic ketones in acrylonitrile have been measured over the entire range of composition at 308.15 K. From these experimental results, parameters such as the isentropic compressibilities K S , interaction parameter χ 12, Flory parameters, A i coefficients, standard deviations σ(Y E), and molar sound

The present paper represents a brief review of life saving system in roll- over accidents, while driving on the road by a four wheeler. An Airbag is an automotive safety restraint system for an occupant as well as passengers. The system consists of a flexible fabric envelope or cushion, designed to inflate rapidly during an automobile collision. Its purpose is to cushion occupants during a crash and provide protection to their bodies when they strike interior objects such as the steering wheel or a window etc. Thus it lowers the number of injuries by reducing the force exerted by steering wheel, windows and the dashboard at any point on the body. Continuing research and developments are going on in its module design, combustible material, air bag fabric design and material, coating etc. in making this life saving safety device further efficient. However, success of any safety restraint device depends on its correct implementation and certain safety rules to be followed.

The causes of collision and electrocution accidents involving birds and power lines, and measures to mitigate such accidents, are reviewed. It is convenient to group the causes according to (1) biological, (2) topographical, (3) meteorological and (4) technical aspects. As regards collisions with power lines, the important biological variables are connected with the morphology, aerodynamic capability, physiology, behaviour and life-history strategies of birds. To understand the electrocution problem, the relationship between body size and electrocuting installations must be considered.Removing earth wires (and modifying earthing methods). modifying line, pole and tower design, installing underground cables and conspicuous marking of lines, poles and towers are important measures for tackling the problems. The route planning process should include careful mapping of (1) topographical features which are leading lines and flight lanes for migrating birds and/or are important for local movements of resident species, (2) topographical elements such as cliffs and rows of trees that force birds to fly over power lines, (3) primary ornithological functions or uses of the area to avoid key areas for birds and avoid separating these areas and (4) local climatic conditions (including seasonal variations) like fog frequency and prevailing wind direction. The outcome depends largely on a combination of these factors.Objective assessment of the effects of mitigating measures, in particular wire marking, is required. The mitigating efforts should be directed against species known to be potential collision victims, and their design should be the result of a careful analysis of the biology and ecology of the target species.Because of the cumulative effects of negative impacts on bird populations today and the alarming number of species with endangered or vulnerable status being killed in connection with utility structures, the problem deserves increased general awareness.

Accompanying appendix to presentation July 2013 to the National Academy of Forensic Engineers Advanced Accident Reconstruction Special Seminar. Appendix demonstrates methodology presented, calculation methods and statistical evaluation of methodology to actual collision tests.

Presentation during July 2013 National Academy of Forensic Engineers Advanced Accident Reconstruction Seminar Series. Development of methods for determining the impact speeds and severity levels of minor damage accidents using a specially developed Force-Deflection analysis methodology that incorporates impact restitution and tire force contributions into the collision event. Examples to vehicle-to-vehicle testing are provided.

Mount Mundo Perdido, a 1750 m-high, steep-sided massif situated in the Viqueque district of East Timor, comprises approximately 30 km2 of complexly juxtaposed rocks deriving from both sides of the collisional plate boundary between the Australian Plate and the Banda Arc. Lithologies include Triassic–Jurassic interior-rift basin deposits, Cretaceous–Oligocene pelagites of Australian passive margin origin, neritic Oligocene–Miocene limestones and volcanics of Asiatic affinity, and Pliocene–Pleistocene synorogenic deposits. Detailed structural mapping shows Mount Mundo Perdido to be dominated by recent, high angle, oblique-slip and strike-slip faults that have been active into the Pleistocene and control the present-day topography. The fault architecture and stratigraphic distribution in the study area are comparable to pop-up structures developed at restraining bends, in this case within an east–west oriented zone of sinistral strike-slip. Our observations, supported by comparisons to scaled sandbox models and to similar pop-up structures developed in strike-slip systems elsewhere in the world, suggest that plate boundary-parallel strike-slip deformation is an integral part of the kinematics within the collisional zone between the Australian and Eurasian/Pacific plates in the Timor region.

Sheet metal products are widely used in various industries nowadays. Among those, bent parts are made by performing linear bends on the sheet metal blanks prepared according to the unfolding of the corresponding designs. Process planning for bent parts consists of closely related tasks, such as unfolding generation, operation parameters and tool selection, bend sequencing and tolerance verification. Aiming at an automated process planning system (CAPP) for bent parts, the aspects of tool selection and dimensional accuracy verification have been tackled in this study. Regarding the aspect of tool selection, due to the requirements in the industry, both part complexity and tool variety for bending have increased. This fact hinders the use of simple Group Technology in mapping compatible and collision-free tools to bend lines merely based on part descriptions. Meanwhile, the interrelation between tool selection and bend sequencing makes automated tool selection a combinatorial problem. In this context, reactive approaches in tool selection, such as open selection during bend sequencing or selection based on a predefined bend sequence, cannot provide feasible tool solutions within an acceptable time span. The current research has resulted in a proactive strategy to downscale the problem complexity. According to this strategy, tools are preselected based on the analysis of part geometries. By detecting collision prone details residing in bent parts, collision scenarios are identified for this preselection step. Furthermore, the initially selected tools are refined according to the collisions detected while planning for a bend sequence. A generic approach is proposed for tool selection based on the evaluation of the encountered collision scenarios. Such collision scenarios are predicted based on either the envisaged part geometry or the intermediate part shapes calculated respectively in the preselection or the refined selection phases. Applying the developed methods for analysing the part and tool geometries in the process, the algorithms proposed for the tool selection procedure in this study are able to swiftly identify the potentially feasible tools for the foreseen collision scenarios. Subsequently, a set of rules has been composed and can be selectively triggered to identify the requirements for the tool parameters to overcome the different collision scenarios.

In this paper, we propose a new hash function based on RC4 and we call it RC4-Hash. This proposed hash function produces variable length hash output from 16 bytes to 64 bytes. Our RC4-Hash has several advantages over many popularly known hash functions. Its efficiency is comparable with widely used known hash function (e.g., SHA-1). Seen in the light of recent attacks on MD4, MD5, SHA-0, SHA-1 and on RIPEMD, there is a serious need to consider other hash function design strategies. We present a concrete hash function design with completely new internal structure. The security analysis of RC4-Hash can be made in the view of the security analysis of RC4 (which is well studied) as well as the attacks on different hash functions. Our hash function is very simple and rules out all possible generic attacks. To the best of our knowledge, the design criteria of our hash function is different from all previously known hash functions. We believe our hash function to be secure and will appreciate security analysis and any other comments.

"PURPOSE:

To evaluate the accuracy of detecting cephalometric landmarks automatically by computer.
MATERIALS AND METHODS:

Digital image processing algorithms (edge-based and morphological) in addition to mathematical algorithms (knowledge-based) were used to develop a program for the identification of 15 lateral cephalometric landmarks on digital cephalograms.
RESULTS:

The automatic landmark identification system was clinically acceptable (p > 0.05 comparing with 2-mm error range) for five landmarks.
CONCLUSION:

The automatic landmark identification is accurate for only some landmarks. Additional studies may be necessary to improve this method."

A calculation model to simulate nonsymmetric ship collisions, implying an arbitrary impact location and collision angle, is described in the paper. The model that is introduced is based on the time integration of twelve equations of motion, six for each ship. The motions of the ships are linked together by a mutual contact force. The contact force is evaluated as an integral over the surface tractions at the contact interface. The calculation model provides full time histories of the ship motions and the acting forces. Physical understanding of the underlying phenomena was obtained by a series of model-scale experiments in which a striking ship collided with an initially motionless struck ship. In this paper, numerical simulations of four nonsymmetric collisions are presented and the calculations are validated with the results of the experiments.